Wash the cucumbers thoroughly and slice them thinly into rounds or half-moons.

Peel and slice the red onion into thin slivers and place in a large mixing bowl.

In a medium bowl, mix the Greek yogurt with the lemon juice and zest until smooth.

Add chopped dill, salt, pepper, and minced garlic (if using) to the yogurt mixture and whisk until well combined.

Pour the dressing over the cucumbers and onion, gently tossing to coat evenly.

Cover with plastic wrap and chill in the refrigerator for at least 30 minutes before serving.

After chilling, give the salad a final stir and serve in individual bowls or on a platter.