01 - In a medium bowl, combine grated cucumber (squeeze out excess liquid), Greek yogurt, garlic, dill, mint (if using), olive oil, lemon juice, salt, and pepper. Mix well and refrigerate to chill while preparing the meatballs.
02 - In a large bowl, combine the ground turkey, grated onion, minced garlic, breadcrumbs, egg, parsley, dill, oregano, cumin, lemon zest, salt, and pepper. Mix until just combined—do not overwork the mixture to keep the meatballs tender.
03 - Form the mixture into 20 to 24 small meatballs, about 1 tablespoon each, rolling gently between your palms for uniform shape.
04 - To pan-fry: Heat olive oil in a large skillet over medium heat. Add the meatballs in batches, turning to brown on all sides, about 8 to 10 minutes until cooked through. To bake: Preheat oven to 400°F. Place meatballs on a greased baking sheet and drizzle with olive oil. Bake for 18 to 20 minutes or until golden and cooked through to an internal temperature of 165°F.
05 - Serve the meatballs hot with chilled tzatziki sauce, lemon wedges, and a garnish of fresh herbs. Accompany with pita bread or a side salad if desired.