Position 2 racks near the center of the oven and preheat to 475ºF. Line to baking sheets with parchment paper, set aside.
In a large bowl, combine the ground chicken, scallions, garlic, ginger, five spice, salt, eggs, panko, soy sauce, and sesame oil. Use your hands to mix all the ingredients together. It's easier to tell when the ingredients are combined when using hands. Do not overmix, it will result is drier meatballs.
Shape the meat mixture into balls, about 3 tablespoons of meat per ball. You could also do this with an ice cream scoop. Place shaped meatballs on prepared baking sheet. Bake for 11-13 minutes or until the meatballs are completely cooked.
While meatballs are baking prepare the sauce. Combine all the ingredients for the sauce in a small saucepan and bring to a boil over medium heat. Reduce the sauce by 1/4, about 3-4 minutes once the sauce boil. When the sauce has thicken remove from heat.
Using 2 tablespoons, dip each individual meatball into the sauce. Alternately, you can brush each meatball with the sauce. Place back on the baking sheet and bake for an additional 2 minutes. Sprinkle with additional scallions and sesame seeds. Serve warm.