In large, non-stick skillet or wok, cook and continue stirring beef in oil over high heat, about 5 minutes. Reduce heat to medium-high. Add Rio Star grapefruit sections, green onions, and ginger and stir together 2 minutes.
Add teriyaki sauce and broccolini and continue to stir-fry over medium-high heat until broccolini is tender. Serve over cooked brown rice.