Preheat oven to 350 degrees F.
Spray a rimmed 18 by 13-inch baking sheet with non-stick cooking spray.
In a medium mixing bowl whisk together soy sauce, cornstarch, ketchup, pineapple juice concentrate, brown sugar, rice vinegar, cornstarch worcestershire, garlic, ginger, and pepper.
Place red and green bell peppers, red onion and chicken on baking sheet then pour sauce over top and toss to evenly coat.
Cook in preheated oven 10 minutes, remove from oven and toss.
Sprinkle in pineapple. Return to oven, continue to cook until chicken is cooked through, about 7 - 10 minutes longer.
Remove from oven toss once more to coat with sauce.
Serve warm over coconut rice if desired.