Score the flank steak the diagonally on both sides. Cut the steak across the grain (this is also usually on the diagonal) into strips about 3 inches wide. Once all tenderizing cuts have been made, cut into serving sized pieces still large enough to grill.
Mix vegetable oil and sugar together in gallon sized Ziplok bag. Add flank steak and soak for 20 minutes (this tenderizes the meat).
Meanwhile mix remaining ingredients as marinade. Add mix to steak in bag and refrigerate for 4 hours, turning occassionally. Grill over hot fire about 2 minutes per side.