Place the turkey, onion, bread crumbs, eggs, garlic powder, salt, and black pepper in a large bowl.
Using your hands, knead all the ingredients together until well blended.
If the mixture doesn't hold together, add a bit more bread crumbs.
Make 18 meatballs approximately the same size.
In a large skillet, heat the olive oil to a medium temperature.
Add the meatballs and stir until brown on all sides.
Cover and allow them to simmer for 10 to 15 minutes.
Place the meatballs on a platter and top with the plum sauce, scallions, and sesame seeds.
Serve at once with noodles or brown rice.