In a bowl, combine salt, sugar, pepper, and the first amount of dulse flakes. Mix until evenly distributed. Set aside until needed.
Lay out a large piece of plastic wrap. In the center, spread out 1/2 cup of curing mixture equal to the dimensions of the salmon. Top with salmon, skin side down.
Cover flesh side of salmon with another 1/2 cup curing mixture. Wrap up in plastic tightly and place in a shallow hotel pan. Insert another pan over the salmon and top with a 3-pound weight. Refrigerate for 12 hours.
Unwrap salmon, remove curing mixture, and pat salmon dry. Repeat steps 2 and 3 with new curing mixture and refrigerate for 12 hours. Repeat this one more time, for a total of 3 rounds.
Unwrap salmon after the third round of curing and remove the curing mixture. Rinse, and pat salmon dry. Return to refrigerator uncovered to air-dry for 2 to 3 hours.
Season flesh side of salmon with second amount of dulse flakes and black pepper. Wrap and refrigerate until needed. Serve as desired.
