In a small dry skillet, slowly toast the sesame seeds over low heat stirring occasionally until brown. Then grind the seeds with a mortar and pestle
combine ground seeds with all the remaining ingredients except the beef in a large bowl and mix thoroughly and set aside.
Slice steak very thinly, cutting diagonally across the grain of the meat from top to bottom. You want lots of small tasty bites of meat. Add the meat to the marinade and stir until all the slices are coated and let stand at room temperature for 20-30 minutes.
Grill the meat over charcoal or under oven broiler no more than 1 minute per side until browned.