Place the frozen meatballs into the slow cooker so they form an even layer on the bottom.
Scatter the drained pineapple chunks over the meatballs.
Add the brown sugar, ginger paste, minced garlic, soy sauce, and rice wine vinegar to the slow cooker.
Pour the barbecue sauce over the ingredients and gently stir so the meatballs are coated in the sauce.
Cover and cook on high for 2 to 3 hours, stirring occasionally so the sauce evenly coats the meatballs.
Spoon the meatballs into a serving dish and garnish with sliced green onions before serving.