1. Heat a large nonstick skillet over medium-high heat. Coat steak with cooking spray. Cook steak in pan over medium-high heat 3 minutes or until browned and liquid has almost evaporated, stirring occasionally.
2. While steak cooks, combine hoisin sauce and next 5 ingredients in a small bowl. Cut onions crosswise into 1-inch pieces. Add sauce mixture and onions to meat in pan; cook 1 to 2 minutes or until sauce is slightly reduced (do not overcook meat). Serve immediately.