How to Make It
Light a grill or preheat a grill pan. Arrange the cutlets and onion on a large baking sheet. Brush all over with the oil and season with salt and pepper. Season the cutlets with the chile powder.
Grill the onions over moderately high heat, turning once, until charred and tender, about 8 minutes. Transfer to a cutting board and cover with foil to keep warm. Grill the cutlets, turning once, until just cooked through, about 2 minutes.
Transfer the pork to the cutting board. Coarsely chop the onions and cut the pork into 1/2-inch strips; transfer to a platter. Serve with the tortillas, avocado, cilantro, sour cream and lime wedges.