Combine first 7 ingredients in a shallow dish or large heavy-duty zip-top plastic bag; add flank steak. Cover or seal, and chill 8 hours, turning steak occasionally.
Remove steak from marinade, discarding marinade. Sprinkle steak with salt and pepper.
Grill, covered with grill lid, over medium-high heat (350° to 400°) 4 to 6 minutes on each side or to desired degree of doneness. Let stand 5 minutes.
Cut steak diagonally across the grain into thin strips.