Begin by adding all the ingredients for the marinade into a bowl and mixing together thoroughly. Next, add your skirt steak to a food safe bag/bowl along with the sliced scallion stalks. Pour in your marinade and mix together to coat all the steak. Seal and place in the fridge for at least 4 hours but ideally overnight.
Preheat your fire to high heat (around 400F) for direct grilling.
Pull your steaks out of the bag and discard any excess marinade. Add your steaks to the grill to cook for about 2-2.5 minutes per side or until they are 125F internal. Once done, pull the steaks off and let them rest for 10 minutes. Once rested, slice your steaks against the grain then into bite size cubes.
For the crunch wrap, lay out a warm large tortilla and place a handful of the grilled steak in the center. Drizzle some warm nacho cheese over the steak, then add your tostada on top making sure all of the steak is underneath the tostada. Top the tostada with a layer of sour cream then add the shredded lettuce, diced tomatoes and shredded cheese. Finally, begin folding the large tortilla over the food to make the crunch wrap shape. If your tortilla is not large enough, add another smaller tortilla to the top before wrapping. Once wrapped, carefully place to the side with the folded side down and repeat all the steps for the rest of the crunch wraps.
Get a cast iron skillet over the coals for a medium high heat. Add your crunch wraps, folded side down, to the skillet to toast for 1-2 minutes until golden brown. Flip over and toast for another 1 minute. Pull off and let cool
Slice, serve and enjoy!