Position a rack in the oven 3 inches from the broiler. Line a half sheet pan with aluminum foil and place the salmon on the pan.
Place the sugar, zest, salt, and pepper into the bowl of a small food processor and process for 1 minute or until well combined. Evenly spread the mixture onto the salmon and allow to sit for 45 minutes, at room temperature.
Turn the oven on to the high broiler setting for 2 minutes. After 2 minutes, place the salmon into the oven and broil for 6 to 8 minutes or until the thickest part of the fish reaches an internal temperature of 131 degrees F on an instant-read thermometer. Remove the salmon from the oven and allow to rest, uncovered, for 8 to 10 minutes. Serve immediately.