Wash and dry the cucumbers and tomatoes. Slice the cucumbers into thin rounds or half-moons and cut the tomatoes into wedges or halves.

Slice the red onion thinly. Soak onion slices in cold water for about 10 minutes, then drain if a milder taste is preferred.

In a large mixing bowl, combine cucumbers, tomatoes, and red onion. Toss gently to mix.

In a separate bowl, whisk together olive oil, red wine vinegar or lemon juice, salt, and black pepper. Add minced garlic if using.

Pour the dressing over the salad and gently toss to coat all ingredients.

Sprinkle chopped parsley over the salad. Mix gently to combine.

Let the salad rest for 10-15 minutes or serve immediately.