Fish: Cut the fish into bite-sized pieces and mince 1 onion. Heat 1 tablespoon oil in a large skillet over medium high heat. Add the onion and saute for 1 minute. Add the fish and sprinkle with cumin, cayenne, salt and pepper to taste. Cook, flipping occasionally and draining any excess liquid, for 5-10 minutes or until the pieces are golden brown on the outside and white all the way through. Set aside.
Vegetables: Chop the bell peppers and 1 onion into bite-sized pieces. Heat 1 tablespoon oil in a large skillet and saute the peppers and onions for 5-10 minutes, until golden brown on the outside and tender-crisp. Chop the pineapple into bite-sized pieces and add to the pan, cooking for another few minutes. Set aside.
Sauce: Combine the vinegar, ketchup, sugar, salt, pineapple juice, orange juice, and sweet chili garlic sauce in a large skillet over medium low heat. Simmer for 10 minutes. Whisk the cornstarch into a few tablespoons of water until smooth. Add to the sauce in the skillet and bring to a low boil. Cook for a few more minutes until the sauce is thickened.
Combine the fish, vegetables, and sauce (you might not want all of it - just eyeball whatever looks good) in a large pan or bowl. Serve over brown rice and sprinkle with sesame seeds. I liked mine with extra sweet chili garlic sauce.
Recipe by Make Mine Gluten Free at https://www.makemineglutenfree.com/healthy-sweet-and-sour-fish/