In a medium mixing bowl, whisk together olive oil and red wine vinegar, adding a pinch of salt and black pepper.

Slice the English cucumber thinly, dice the tomato, and finely chop the red onion.

Toss the chopped vegetables in the bowl with the dressing.

Cover the bowl and let the salad rest for 10 to 15 minutes.

Tear fresh basil leaves and sprinkle them over the salad, then toss gently.

Serve immediately in a large bowl or individual plates.