1. In a ziptop bag, combine soy sauce, sugar, sesame oil, garlic, and ginger. Add steak strips and toss to coat. Let marinate in the refrigerator for at least four hours or up to overnight, occasionally smushing around the steak so it’s evenly coated.
2. Heat oil in a sauté pan or grill pan over high heat. Add steak and cook for two to three minutes (they’ll cook fast!).
3. If serving right away, plate meat over rice, drizzle with sauce and top with sesame seeds. (If you’d like to rewarm the meat, combine the meat and marinade in a baking pan and cover.)
4. Serve meat over sushi rice. Top with scallions and sesame seeds.