While you make meatballs, cook rice as per package instructions.
In a medium bowl, whisk pineapple juice, soy sauce, ketchup, rice vinegar, maple syrup and cornstarch. Set aside.
In a large bowl, add ground turkey, oats, egg, dried oregano, salt and pepper. Using spatula or your hands, mix well until combined. Using a trigger scoop, form about 26 meatballs.
Preheat large skillet or Dutch oven on medium-high heat and swirl oil to coat. Fry meatballs until golden brown on both sides, working in batches. Transfer onto a large plate.
Add oil, onion and bell pepper. Saute for 4-5 minutes or until a bit golden. Add pineapple, give sauce another whisk and pour it in, and add previously browned meatballs. Give a gentle stir and bring to a boil. Then cover and simmer for 10 minutes.
Garnish with green onion and serve over rice.
Notes
Store: Refrigerate in an airtight container for up to 5 days.
Freeze: Fully cook, cool completely and freeze in an airtight container for up to 3 months. Thaw on a stovetop covered on low.