Preheat oven to 350 degrees. Line pan with foil. Place salmon fillet on foil. Generously spread a layer of mayonnaise over entire top surface of salmon. Generously sprinkle furikake over mayonnaise. Bake for 25 minutes (if salmon piece is over 2 lbs, bake 35 minutes).
1 tbsp sugar
2 tbsp shoyu
1/2 tbsp butter
Combine glaze ingredients in a heat-proof cup. Microwave on high for 30 seconds. Let cool 5 minutes. Pour over cooked salmon.