Wash the cucumbers and red onion thoroughly. Finely slice the cucumber into half-moons and the onion into thin rings, then set aside in a large mixing bowl.

Dice or shred the cooked chicken breast and mince the garlic if using fresh. Combine with the sliced vegetables in the mixing bowl.

In a separate bowl, mix Greek yogurt, lemon juice, and olive oil. Season with salt and pepper to taste, and stir until smooth.

Pour the dressing over the chicken and vegetable mixture and gently fold together until everything is evenly coated.

Optionally, add lemon zest, fresh herbs, or nuts for extra flavor and texture.

Cover the bowl and refrigerate for at least 15-20 minutes before serving.