Slice meat across the grain into 1/4-in. strips. In a resealable plastic bag, combine the teriyaki sauce, oil, garlic, ginger and red pepper flakes; add meat. Seal bag and turn to coat; refrigerate for 8 hours or overnight, turning several times.
Drain and discard marinade. Thread meat onto four metal or soaked wooden skewers. Using long-handled tongs, moisten a paper towel with cooking oil and lightly coat the grill rack.
Grill meat, covered, over medium heat or broil 4 in. from the heat for 2-4 minutes on each side or until meat reaches desired doneness. Remove from grill and sprinkle with sesame seeds.