How to Make It
Light a grill. When the coals are hot, grill all the chiles, turning, until blistered and blackened all over, about 2 minutes per side; be careful not to burn the thin-skinned chiles. Discard the charred skins, stems and seeds and coarsely chop the chiles.
Over a medium-hot fire, grill the tomatillos and tomatoes, cut side down, until lightly charred and tender, about 4 minutes. Turn and grill, skin side down, for 1 minute. Grill the onion, turning, until lightly charred and tender, about 15 minutes. Coarsely chop the vegetables and put them in a bowl. Add the chiles, cilantro and lime juice and season with salt and pepper.
Using a damp paper towel, coat the grill with the oil. Season the salmon with salt and pepper and grill over a medium-low fire, turning once, until crusty brown and slightly rare inside, about 6 minutes per side. If using a fillet, cut it into 4 pieces. Serve the salmon with the salsa and lime wedges.