Preheat oven to 400 degrees F. Line baking sheet with aluminum foil, and spray foil with cooking spray.
Place salmon fillets skin-side down on the foil. (Skinless fillets are fine too.) Sprinkle fish with salt, then squirt a stripe of mustard and a stripe of honey on top. Use your fingers to evenly spread the honey and mustard all over the top and sides of the fish.
Bake in preheated oven for 15 minutes, then broil for 5 minutes longer. If fillets had skin, gently slide a spatula between the meat and skin to easily remove fish for serving. Enjoy!