Wash cucumbers and tomatoes under cool running water. Slice cucumbers thinly, aiming for 1/4-inch rounds. Cut tomatoes into bite-sized pieces.

Slice the red onion thinly. Optionally soak in cold water for about 10 minutes, then drain.

In a large mixing bowl, gently toss together cucumbers, tomatoes, and red onion.

In a separate small bowl, whisk together olive oil, vinegar or lemon juice, salt, and pepper. Optionally add minced garlic.

Pour dressing over the vegetable mix and toss gently to coat.

Fold in freshly chopped herbs if using, aiming for even distribution.

Let the salad sit for 10-15 minutes at room temperature to allow flavors to meld, or serve immediately.