01 - Preheat oven to 400°F. Line a baking sheet with parchment paper and set aside.
02 - In a large mixing bowl, combine ground chicken, breadcrumbs, egg, green onions, garlic, soy sauce, ginger, salt, and pepper. Mix gently until just combined, being careful not to overwork the mixture.
03 - Form the mixture into 20 uniform bite-sized meatballs and place them on the prepared baking sheet, spacing them evenly.
04 - Bake for 18-20 minutes until fully cooked through and golden brown on the outside.
05 - While the meatballs bake, combine pineapple juice, pineapple chunks, ketchup, brown sugar, rice vinegar, and soy sauce in a saucepan over medium heat. Bring to a gentle simmer.
06 - Whisk in the cornstarch slurry and cook, stirring frequently, until the sauce thickens to a glossy glaze, about 2-3 minutes.
07 - Transfer the baked meatballs to the saucepan and toss gently until evenly coated with the pineapple sauce.
08 - Serve hot, garnished with chopped cilantro or parsley and a sprinkle of sesame seeds if desired.