In a medium mixing bowl, combine beef and marinade ingredients. Let marinate for at least 30 minutes or up to overnight, covered in the fridge.
In a small bowl, combine sauce ingredients and set aside.
In another small bowl, dissolve 2 teaspoons cornstarch in 1 tablespoon cool water to make a slurry. Set aside.
In a wok or large frying pan on medium high heat, add 2 tablespoons avocado, vegetable or canola oil. Add half the beef and stir fry until 70-80% cooked. Remove and set aside. Add 1 tablespoon cooking oil and repeat with remaining beef. Remove and set aside.
Add another tablespoon cooking oil. Add onion to the wok and stir fry for 1 minute. Add ginger, garlic and black beans, stir fry for 30 seconds. Stir in red and orange peppers and cook for another about 1-2 minutes.
Push the vegetables to the side and add the sauce in the middle. Once the sauce is bubbling, stir in the slurry. Add the cooked beef along with the drippings and cook until the sauce starts to simmer and thicken, and meat is cooked through, about another 1-2 minutes. Turn off the heat.
Serve with rice.