Heat a grill or a large cast-iron skillet. Place all the chilies on the grill or in the skillet, and heat, turning once or twice, to toast them. Do not allow them to burn. Remove the chilies, split them in half and discard the stems. Remove and reserve the seeds.
Return the split chilies to the grill or skillet, and lightly toast the insides. Cut up the chilies in small pieces.
Place the chilies with the seeds, garlic, scallion, vinegar, water, oregano, thyme and bay leaves in a blender, and process until well blended.
Heat the oil in the skillet, add the chili mixture and cook, stirring, about 5 minutes. Remove from the heat and allow to cool 10 to 15 minutes. Season lightly with salt if desired.
Place the salmon in a shallow bowl, and coat with the chili mixture. Allow to marinate at room temperature 20 to 30 minutes.
Preheat a grill or broiler. Grill or broil the salmon, skin side first, close to the source of heat, until the outside is browned and the fish is just cooked on the inside, 3 to 4 minutes on each side.