Place the steak in a glass or nonreactive baking dish. In a food processor or blender add all the marinade ingredients and blend until smooth. and pour the marinade over the steak. Cover and marinate for 2-8 hours or overnight.
For best results preheat an outdoor grill. The oven broiler or a cast iron skillet can also be used. Place steaks on the grill, season again with salt and pepper. Cook approximately 4-6 minutes per side.
It is best to take the steak off the grill just slightly under your preferred temperature. It will continue to cook while resting. Let it rest a few minutes tented loosely with aluminum foil. Once ready, cut the steak into slices about 1/8-1/4 inch thick against the grain.
While steak is cooking, warm tortillas for about 30 seconds on each side in a skillet or on the grill. Stack the tortillas and move to the side or wrap in foil to keep warm.
To assemble the tacos add slices of steak, chopped onions, cilantro, salsa and cheese to each tortilla. Finish with a squeeze of fresh lime and a dash of your favorite hot sauce.
As they say in Mexico, Buen Provecho! (Enjoy!)