Preheat grill to high, adding on a grill pan for the sprouts. Cut skirt steak into manageable pieces, 6-8 inches long. Salt all sides and let rest at room temperature for 30 minutes before cooking if possible.
As meat rests, make the chimichurri sauce. Place cloves of garlic into blender or food processor. Mince. Add in vinegar, parsley, and scallion. Process and slowly add in olive oil. Once oil is added, add in pepper flake, oregano, salt and pepper to combine. Chill until service.
Place the Brussels sprouts into a large, microwave safe mixing bowl and heat in the microwave on high for 2 minutes. Mix with garlic powder, apple cider vinegar, and a pinch of salt and pepper. Place into the grill pan and grill for 10 minutes, stirring often. The leaves will char; that’s the best part! Additionally, grill the steak for 3 to 5 minutes on each side, until done to the degree of doneness you prefer (I would go 3 minutes a side, but that’s me).
Once the food is done, let the skirt steaks rest for 5 minutes, then slice very thinly against the grain of the meat (this is important, use an electric knife if you have one). Serve with chimichurri along side sprouts.