Get the grill very hot by turning on all burners to high, for 15 minutes.
Return to the grill and leave the primary burner on high, but turning all other burners to low.
Clean and oil grill.
Place peppers and onions on the HOT burner.
Place tortilla pack on the LOW burner.
Close the lid and cook for 10 minutes - flip tortillas and vegetables after 5 minutes of cooking.
After 10 minutes of grilling, remove vegetables and place in an aluminum, disposal pan. Remove tortillas and set aside.
Close grill to heat up grates again for 5 minutes. Meanwhile, cover the vegetable pan with aluminum foil and secure.
After 5 minutes, place meat over the HOT burner of the grill. Place the aluminum foil pan, with the vegetables on the LOW burner of the grill.
Close the lid and grill for 4 minutes. Flip the meat - you should have a great sear with grill marks on the meat. Close the grill and cook an additional 4 minutes.
Grill to an internal temperature of 135ºF.
Remove meat and vegetables from grill. Tent meat and allow to rest for 5 minutes.
Thinly slice the steak, AGAINST THE GRAIN - place on a platter.
Julieanne the bell peppers, so they are in strips. Remove the toothpicks from the onion and gently pull apart. Pour reserved marinade over the vegetables. Add 1 Tablespoon chopped, fresh cilantro. Gently stir. Add vegetables to a serving platter. Serve with tortillas.
Optional toppings: avocado, sour cream, lime wedges, pico de gallo.