Cut thin strips of the rind off one of the oranges with a vegetable peeler. Cut the rind into very thin pieces (about ¼ cup). Squeeze juice from both oranges and set aside.
In a small bowl, whisk together ⅓ cup of the broth, the orange juice, soy sauce, cornstarch and pepper flakes..
Heat a wok or large nonstick skillet over medium-high heat until a drop of water sizzles in the pan. Add the oil and swirl to coat the pan. Add the beef and stir fry until lightly browned, about 4 minutes, then transfer to a plate and cover with foil.
Add the beans, bell pepper, orange rind, and remaining ⅓ cup of broth to the pan. Cook, covered for 2 to 3 minutes. Uncover and add green onions, ginger and garlic. Stir fry until fragrant, about 30 seconds.
Re-whisk the orange juice mixture. Return the beef to the pan along with the orange juice mixture. Stir fry until the sauce bubbles and thickens, about 1 minute. Serve over ½ cup rice