This cucumber tomato onion salad is fresh, crisp, and ready in 10 minutes. A light red wine vinegar dressing ties everything together — the perfect simple summer side dish.
This is the salad I make more than any other during summer. Not because it’s fancy — it’s about as simple as a salad gets. But there’s something about the combination of cold crisp cucumber, ripe juicy tomatoes, and sharp red onion in a tangy vinegar dressing that works perfectly alongside almost anything coming off the grill.
My grandmother made a version of this every summer. Hers was just cucumbers, tomatoes, onion, vinegar, salt, and a pinch of sugar. That’s still the base of this recipe. I’ve added a little olive oil and fresh dill because I think it makes it better, but the heart of it hasn’t changed.
It takes about 10 minutes to put together and tastes better after it sits for 30 minutes in the fridge, which makes it one of those rare side dishes you can actually prep ahead. Serve it with grilled chicken, burgers, salmon, or honestly anything. It goes with everything.
➡️ You should try this recipe next: Watermelon Cucumber Feta Salad Fresh and Easy
Why You’ll Love This Recipe
- Only 10 minutes of prep and no cooking at all
- Tastes better after sitting — one of the few salads that actually improves ahead of time
- Works alongside grilled meat, fish, sandwiches, or anything else on the table
- Light, fresh, and not heavy at all
- Naturally vegan and gluten free
- Keeps in the fridge for 3 days
What You Need
English cucumber is the best choice here. The skin is thin enough that you don’t need to peel it, and the seeds are small and not watery the way regular garden cucumbers can be. Slice it thin — about ¼ inch — so it absorbs the dressing well. Persian cucumbers work just as nicely and are slightly crunchier. If you only have a regular cucumber, peel it and scoop out the seedy center before slicing.
Tomatoes need to be ripe. This salad is simple enough that the quality of the tomatoes matters. In summer, cherry tomatoes halved or a couple of good ripe Roma tomatoes cut into chunks both work. Avoid watery, pale tomatoes — they’ll dilute the dressing and make the whole salad taste bland.
Red onion adds a sharp bite that the salad needs. Sliced very thin so you get the flavor without the overwhelming raw onion punch. If raw onion is too strong for your taste, soak the slices in cold water for 10 minutes before adding — it takes the edge off significantly without losing the flavor.
Red wine vinegar is the dressing base. It has the right level of acidity and a slightly fruity quality that works well with summer vegetables. White wine vinegar or apple cider vinegar both work as substitutes.
Olive oil rounds the dressing out and keeps it from being too sharp. Just a couple of tablespoons — this is a light vinaigrette, not a heavy one.
Sugar — just half a teaspoon — balances the acidity of the vinegar. It doesn’t make the salad sweet, it just keeps the dressing from tasting harsh.
Fresh dill or parsley scattered over the top. Dill is my preference here — it has an affinity with cucumber that’s hard to beat. Fresh parsley works if dill isn’t your thing.
How to Make It
Slice the cucumber thin. Halve the cherry tomatoes or cut larger tomatoes into rough chunks — not too small, you want pieces with some substance. Slice the red onion as thin as you can get it.
If you want to mellow the onion, put the slices in a small bowl of cold water right now and let them sit while you prep everything else.
In a small bowl whisk together 2 tablespoons red wine vinegar, 2 tablespoons olive oil, ½ teaspoon sugar, ½ teaspoon salt, and black pepper. Taste it. It should be tangy and bright with just a slight sweetness underneath.
Add the cucumber, tomatoes, and drained onion to a large bowl. Pour the dressing over and toss to coat. Scatter fresh dill or parsley over the top.
At this point you can serve it immediately or refrigerate it for 30 minutes first. I almost always do the 30 minutes — the vegetables soften slightly and absorb the dressing and the whole thing tastes more cohesive. Not long enough to go soggy, just long enough to come together.
If you’re making this for a summer spread, it pairs really well alongside the taco salad or as a lighter counterpoint to something richer like creamy smothered chicken and rice. The vinegar dressing cuts right through anything heavy.
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Tips
Slice the cucumber and onion thin. Thick pieces don’t absorb the dressing the same way and the texture is less pleasant. A mandoline makes this fast and consistent but a sharp knife works perfectly fine.
Use ripe tomatoes. The tomato is doing a lot of flavor work in a salad this simple. An underripe, pale tomato makes a dull salad. A ripe, sweet summer tomato makes the whole thing.
Let it sit before serving. 30 minutes in the fridge is the move. The vegetables release a little of their liquid, the dressing gets absorbed, and the flavors meld in a way that doesn’t happen with immediate serving.
Taste the dressing before tossing. Vinegar levels vary by brand. Taste and adjust — more sugar if it’s too sharp, more salt if it tastes flat, a tiny bit more olive oil if it seems harsh.
Don’t add the herbs too far in advance. Fresh dill and parsley wilt and turn dark if they sit in the dressing for too long. Add them right before serving for the best color and freshness.
Variations
Add feta cheese. Crumbled feta scattered over the top adds saltiness and creaminess that takes this from a simple side to something a bit more substantial. If you like that combination, my watermelon cucumber feta salad takes the same idea in a slightly sweeter summer direction.
Add avocado. Diced avocado folded in gently right before serving adds richness and healthy fat. Add it at the last minute since avocado doesn’t hold well once dressed.
Make it Greek style. Add kalamata olives, a sprinkle of dried oregano, and some feta. Swap the red wine vinegar dressing for lemon juice and olive oil. Serve with warm pita.
Add chickpeas. A can of chickpeas drained and rinsed tossed into the salad adds protein and makes it more filling as a standalone lunch rather than just a side dish.
Use a different herb. Fresh basil works beautifully with tomato and cucumber. Fresh mint adds a cool brightness that’s excellent in summer. A mix of whatever fresh herbs you have on hand always works.
Make it creamy. Swap the vinegar dressing for a simple mix of sour cream or Greek yogurt thinned with a little white vinegar and dill. A completely different direction — cool, creamy, and excellent alongside grilled salmon or salmon teriyaki.
Substitutions
English cucumber can be replaced with Persian cucumbers (same method, slightly smaller), or regular cucumber peeled and seeded.
Red wine vinegar can be swapped for white wine vinegar, apple cider vinegar, or fresh lemon juice. Each gives a slightly different flavor but the same brightness.
Red onion can be replaced with shallots for a milder bite, or green onions for the most subtle onion flavor.
Fresh dill can be replaced with fresh parsley, fresh basil, or fresh mint. Dried herbs don’t work as well here — the fresh versions have a brightness that dried can’t replicate.
Olive oil can be replaced with avocado oil or any neutral oil.
Storage
This salad keeps surprisingly well in the fridge. Store it covered for up to 3 days. The cucumber and tomatoes release more liquid as they sit, so the dressing gets a bit more dilute over time. Before serving leftovers, taste and add a small splash of fresh vinegar and a pinch of salt to bring it back to life.
It does not freeze — the vegetables become completely watery after freezing and thawing.
If you’re making it ahead for a party, you can prep everything and store the components separately — vegetables in one container, dressing in a jar — and toss together about 30 minutes before serving.
Frequently Asked Questions
Can I make this salad ahead of time?
Yes and it’s actually better that way. Make it up to a few hours ahead and refrigerate. Just add the fresh herbs right before serving so they stay green and fresh. If making it the day before, store the dressing separately and toss it together about 30 minutes before you need it.
Why is my salad watery?
Cucumbers and tomatoes release liquid as they sit, especially once salted or dressed. This is normal. If it bothers you, you can salt the cucumber slices, let them sit in a colander for 15 minutes, then pat dry before dressing — this draws out some of the moisture before it hits the bowl. You can also strain off some of the liquid before serving.
Do I have to peel the cucumber?
Not if you’re using English or Persian cucumbers. Their skin is thin and doesn’t need removing. For regular garden cucumbers, peeling is recommended since the skin can be tough and slightly bitter.
Can I add other vegetables?
Absolutely. Bell pepper adds crunch and sweetness. Radish adds a peppery bite. Corn kernels add sweetness that works really well with the vinegar dressing. Olives add brine. This is a very flexible salad.
What dressing goes best with this?
The red wine vinegar and olive oil dressing in this recipe is the classic for a reason. But Italian dressing from a bottle works fine if you want a shortcut. A simple lemon and olive oil dressing is another great option, especially if you’re serving it alongside fish.
Cucumber Tomato Onion Salad Simple Summer Side Dish
Description
This cucumber tomato onion salad is fresh, crisp, and ready in 10 minutes. A light red wine vinegar dressing ties everything together — the perfect simple summer side dish.
Ingredients
Dressing:
Instructions
- Optional: soak red onion slices in cold water for 10 minutes to mellow the sharp bite. Drain and pat dry before using.
- Slice cucumber thin. Halve cherry tomatoes or roughly chop larger tomatoes. Slice red onion as thin as possible.
- Whisk together red wine vinegar, olive oil, sugar, salt, and pepper in a small bowl. Taste and adjust.
- Add cucumber, tomatoes, and onion to a large bowl. Pour dressing over and toss to coat.
- Refrigerate for 30 minutes if time allows. Add fresh dill or parsley right before serving.
Nutrition Facts
Servings 4
- Amount Per Serving
- Calories 80kcal
- % Daily Value *
- Total Fat 5g8%
- Saturated Fat 1g5%
- Sodium 300mg13%
- Total Carbohydrate 8g3%
- Dietary Fiber 2g8%
- Sugars 5g
- Protein 1g2%
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.
Note
Ripe tomatoes matter more in this salad than almost anything else — the tomato is doing a lot of the flavor work in a recipe this simple.
Let it sit for at least 30 minutes before serving — the vegetables absorb the dressing and the whole salad tastes significantly more cohesive.
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