Slice the cucumbers into thin half-moons or rounds. If the cucumbers have large watery seeds, remove the center before slicing.
Finely slice the red onion and chop the mint leaves.
In a small bowl, whisk together the yogurt, extra virgin olive oil, lemon juice, minced garlic, salt, and black pepper until smooth.
Add the sliced cucumbers, red onion, and chopped mint to a large mixing bowl.
Pour the lemon yogurt dressing over the salad.
Toss gently until the cucumbers and onion are evenly coated.
Taste and adjust with more lemon juice, salt, or pepper if needed.
Chill for 15 to 20 minutes if desired, then serve cold.