Heat the oven to 375 F. In a small bowl, combine the mustard and mayonnaise. In another small bowl, combine the cheese and panko. If the consistency of the cheese and panko is not the same, place the ingredients in a food processor and pulse for 30 seconds.
Coat the top of each salmon fillet with 1 1/2 tablespoons of the mustard mixture and 2 tablespoons of the panko mixture. Sprinkle each fillet with salt and pepper.
Heat a large nonstick pan over medium-high heat. Add oil. Cook fillets for 1 minute or until golden brown. If the pan is ovenproof, place the pan in the oven to finish cooking, or place fillets on a baking sheet crusted side up. Bake for about 6 minutes or salmon flakes with a fork.