Wash the cucumbers thoroughly under running water.
Slice the cucumbers into thin rounds or half-moons.
Rinse the cherry tomatoes and cut them in half.
Peel and thinly slice the red onion.
In a large mixing bowl, combine the sliced cucumbers, halved tomatoes, and sliced onions.
Crumble the feta cheese over the vegetable mixture.
In a small bowl, whisk together olive oil and red wine vinegar.
Drizzle the dressing over the salad mixture.
Season with salt and pepper to taste.
Toss gently to combine all ingredients and ensure even coating.