01 - Wrap the grated cucumber in a clean kitchen towel and squeeze firmly to remove all excess moisture. Combine the drained cucumber with Greek yogurt, minced garlic, fresh dill, lemon juice, and olive oil in a mixing bowl. Season with salt and pepper to taste, stir until smooth, and refrigerate until ready to serve for the best flavor.
02 - In a large mixing bowl, combine the ground turkey, breadcrumbs, egg, minced garlic, grated onion, parsley, mint, dried oregano, cumin, salt, and black pepper. Gently mix with your hands until just evenly combined, being careful not to overwork the mixture.
03 - Roll the turkey mixture into 18 to 20 uniform walnut-sized balls, approximately 1.5 inches in diameter, and set them on a plate or tray.
04 - Heat olive oil in a large nonstick skillet over medium heat. Working in batches to avoid crowding, add the meatballs and cook for 8 to 10 minutes, turning every couple of minutes, until deeply golden brown on all sides and cooked through to an internal temperature of 165°F.
05 - Preheat oven to 400°F. Arrange the shaped meatballs on a parchment-lined baking sheet and brush or spray lightly with olive oil. Bake for 15 to 18 minutes, turning halfway through, until golden and cooked through to 165°F internally.
06 - Arrange the meatballs on a serving platter with a generous dollop of tzatziki sauce alongside. Garnish with fresh herbs and lemon wedges. Serve with warm pita bread or a crisp side salad if desired.