1. Whisk together soy sauce, vinegar, oyster sauce, cornstarch, and sesame oil.
2. In a wok or large skillet, heat vegetable oil over high. Add chicken and cook until browned, 10 minutes. Add ginger, garlic, scallions, and broccoli and cook, stirring frequently, until broccoli is bright green, 3 minutes. Add 1/4 cup water, scraping up browned bits with a wooden spoon. Stir in soy sauce mixture and cook, stirring, until thickened, 1 minute. Serve warm with rice.
Place the rice and water in a saucepan, and bring to a boil. Reduce heat, cover, and cook 20 minutes. In a skillet over medium heat, cook the beef until evenly browned.
Remove and discard the tops, seeds, and membranes of the bell peppers. Arrange peppers in a baking dish with the hollowed sides facing upward. (Slice the bottoms of the peppers if necessary so that they will stand upright.)
In a bowl, mix the browned beef, cooked rice, 1 can tomato sauce, Worcestershire sauce, garlic powder, onion powder, salt, and pepper. Spoon an equal amount of the mixture into each hollowed pepper. Mix the remaining tomato sauce and Italian seasoning in a bowl, and pour over the stuffed peppers.
Bake 1 hour in the preheated oven, basting with sauce every 15 minutes, until the peppers are tender.