1. Place steak in freezer for 15 minutes before slicing.
2. In a wok or large skillet, heat oil over medium high. Add steak and cook, stirring, until browned, about 4 minutes. With a slotted spoon, transfer steak to a plate. Add green beans, ginger, and garlic and cook, stirring until green beans are crisp tender, 5 minutes. Return beef and any juices to pan along with fish sauce and basil. Cook 1 minute. Serve with rice.