Wash and slice the cucumbers into thin rounds. Dice the tomatoes and slice the red onion thinly; soak in cold water for about 10 minutes.

In a small bowl, whisk together olive oil and red wine vinegar or lemon juice. Season with salt, pepper, and minced garlic if desired.

In a large mixing bowl, combine cucumbers, tomatoes, and drained red onions; mix gently.

Drizzle the dressing over the vegetables and toss gently without crushing the tomatoes.

Sprinkle chopped parsley over the salad and lightly toss again.

Let the salad sit for 10-15 minutes before serving, either chilled or at room temperature.