01 - Wrap the grated cucumber in a clean kitchen towel and squeeze firmly to remove excess moisture. In a mixing bowl, combine the Greek yogurt, drained cucumber, minced garlic, fresh dill, lemon juice, and extra-virgin olive oil. Season with salt and pepper, then stir until smooth and well blended. Cover and refrigerate to allow the flavors to meld while you prepare the meatballs.
02 - In a large mixing bowl, combine the ground turkey, breadcrumbs, egg, minced garlic, grated onion, chopped parsley, chopped mint, dried oregano, ground cumin, salt, and black pepper. Gently fold the ingredients together with your hands until just evenly combined, taking care not to overwork the mixture.
03 - Portion the turkey mixture into 18 to 20 uniform, walnut-sized balls, rolling each gently between your palms. Arrange them on a plate or tray and set aside while you prepare to cook.
04 - Heat the 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 the 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 them halfway through, until golden brown and fully cooked through.
06 - Arrange the cooked meatballs on a serving platter alongside a generous bowl of tzatziki sauce. Garnish with fresh herbs and lemon wedges. Serve immediately with warm pita bread or a crisp side salad.