Preheat the oven to 400°F and line a baking sheet with parchment paper.

Combine the ground turkey, oats, egg, feta, garlic, oregano, cumin, salt, pepper and parsley in a large bowl.

Mix gently with your hands just until combined; overmixing makes meatballs tough.

Roll into 1.5-inch balls (about 2 tablespoons each) and space them on the baking sheet.

Bake for 18 to 20 minutes, until the outside turns golden brown and the centers reach 165°F on a meat thermometer.

While the meatballs bake, stir together the Greek yogurt, grated cucumber, garlic, lemon juice, olive oil and salt in a bowl to make the tzatziki.

Let the meatballs rest for 3 minutes on the pan.

Serve warm with the tzatziki alongside for dipping, and skewer with toothpicks if passing on a tray.