In a large mixing bowl, combine the ground turkey, breadcrumbs, grated Parmesan, chopped onion, minced garlic, egg, oregano, salt, black pepper, and cumin. Mix until all ingredients are well incorporated.
Using your hands, form the mixture into small meatballs, about 1 inch in diameter. You should get around 18-20 meatballs.
Heat a large skillet over medium heat and add a drizzle of olive oil. Once the oil is hot, gently place the meatballs in the skillet, making sure not to overcrowd them. You may need to cook them in batches.
Cook the meatballs for about 5-7 minutes on each side, or until they are browned and fully cooked through (internal temperature should reach 165°F). Remove meatballs and set them aside on a paper towel to drain excess oil.
For the tzatziki, in a medium bowl, mix the Greek yogurt, shredded cucumber, lemon juice, dill, and a pinch of salt. Stir until well combined.
Serve the meatballs warm, drizzled with tzatziki on top or on the side, allowing everyone to add as much as they like.
Notes
Plate the meatballs on a large platter, drizzled with tzatziki, and garnish with fresh dill or parsley. Serve with warm pita bread and a side salad for a complete meal.