In large mixing bowl, combine ground turkey, breadcrumbs, egg, minced garlic, chopped onion, parsley, oregano, cumin, salt, and pepper. Mix with clean hands just until incorporated, being careful not to overmix.

Roll mixture into uniform meatballs about 1 to 1.5 inches in diameter. Slightly wet hands prevent mixture from sticking.

For oven method: Preheat oven to 400°F. Place meatballs on parchment-lined baking sheet and bake for 15-20 minutes until golden and internal temperature reaches 165°F.

For pan-frying: Heat drizzle of olive oil in large skillet over medium heat. Cook meatballs 4-5 minutes per side, turning carefully to brown all sides, until fully cooked through.

For tzatziki sauce, grate cucumber and squeeze out as much moisture as possible using paper towels or cheesecloth to prevent watery sauce.

In mixing bowl, combine Greek yogurt, drained cucumber, minced garlic, lemon juice, chopped dill, and olive oil. Stir until evenly mixed, then taste and adjust seasoning with salt and pepper.

Chill tzatziki in refrigerator for at least 30 minutes before serving to let flavors meld. Serve meatballs with generous dollop of tzatziki sauce alongside pita bread, rice, or fresh salad.