Preheat the oven to 400 degrees and line a baking sheet with parchment paper. Soak the wooden skewers in water for 10 minutes.
In a mixing bowl, combine the ground beef, panko breadcrumbs, egg, 2 tablespoons of teriyaki sauce, green onions, and minced garlic. Mix with your hands until the ingredients are evenly distributed.
Divide the mixture into 16 equal portions and roll each into a ball. Thread four meatballs onto each skewer, leaving a small gap between them.
Place the skewers on the prepared baking sheet. Bake for 15 minutes.
Remove the skewers from the oven and brush the remaining tablespoon of teriyaki sauce over the meatballs. Return to the oven for 5 more minutes.
Sprinkle the sesame seeds over the hot skewers before serving.