Puree mango and mustard in a blender and transfer mixture to a shallow container such as a pie plate. Season salmon with salt and black pepper. Heat grapeseed oil over medium-high heat in a large skillet. Dip salmon in mango/mustard mixture and coat with bread crumbs. When the oil begins to shimmer, saute salmon leaving undisturbed for the first 4 minutes or so to allow the seasonings to integrate into the surface of the fish and to allow the caramelization process to begin to prevent "crusting off" of the coating. When you see the edges begin to turn golden, flip the fillets over and cook the other side in the same way. Remove from heat and set aside to carryover cook, or finish in a preheated 325 degree F oven, if necessary.
Transfer to a serving dish and sprinkle with parsley.