In small bowl, whisk soy sauce, olive oil, brown sugar, green onions, sesame seeds, garlic, pepper, and ginger. Pour into a large resealable plastic bag, add steak, seal securely, and turn to coat. Marinate in refrigerator at least 4 hours up to 2 days.
Preheat grill to medium-high.
Remove steak from marinade. Place steak on grill and cook, covered, 5 to 6 minutes per side, until internal temperature reaches 145°F.
Move steak to a serving platter and let rest 5 minutes before cutting into thin slices.