01 - In a medium bowl, combine grated cucumber with excess liquid squeezed out, Greek yogurt, garlic, dill, mint (if using), olive oil, lemon juice, salt, and pepper. Mix thoroughly and refrigerate to allow flavors to meld.
02 - In a large bowl, combine ground turkey, grated onion, minced garlic, breadcrumbs, egg, parsley, dill, oregano, cumin, lemon zest, salt, and black pepper. Mix gently until just combined—do not overwork the mixture to keep meatballs tender.
03 - Shape the mixture into 20 to 24 small meatballs, using approximately 1 tablespoon of mixture per meatball. Place formed meatballs on a tray or plate.
04 - For pan-frying: heat olive oil in a large skillet over medium heat. Add meatballs in batches, turning to brown evenly on all sides, cooking 8 to 10 minutes until cooked through. For baking: preheat oven to 400°F (200°C). Arrange meatballs on a greased baking sheet, drizzle with olive oil, and bake for 18 to 20 minutes until golden and cooked through.
05 - Arrange hot meatballs with chilled tzatziki sauce, lemon wedges, and a garnish of fresh herbs. Serve with pita bread or a side salad if desired.