Preheat grill. Remove the planks from the water and place on the grill until hot. Have ready 4 sheets of aluminum foil cut into 16 by 16-inch sheets. Remove the planks with tongs and place 1 plank in the center of each piece of foil. Brush the salmon on both sides with olive oil and season with salt and pepper to taste. Wrap the aluminum around the salmon, return to the grill and cook for approximately 10 minutes or to medium well doneness. Remove each fillet from the plank and drizzle with the sauce.
In a blender or food processor, combine the peppers, vinegar, garlic, saffron, honey, and mustard and blend 30 seconds. With the motor running, slowly add the oil until it emulsifies. Season to taste with salt and pepper.