Preheat the oven to 400 degrees and line a baking sheet with parchment paper. In a large bowl, combine the ground turkey, panko breadcrumbs, egg, and 1/4 cup of the teriyaki sauce. Mix until the ingredients are evenly distributed, then shape the mixture into 16 meatballs and place them on the prepared baking sheet.

Bake the meatballs for 15 minutes until they are cooked through and lightly browned. While the meatballs bake, warm the remaining 1/2 cup teriyaki sauce in a large skillet over medium heat. Add the pineapple chunks and let them simmer for 3 minutes so the sauce thickens slightly.

Remove the meatballs from the oven and add them to the skillet. Gently toss everything together so the meatballs are coated in the sauce and pineapple. Spoon the meatballs and pineapple over the cooked white rice. Finish with sliced green onions and sesame seeds before serving.