Place the salmon skin side up on plastic wrap. Pat dry with paper towels.
Combine the salt, sugar, pepper, crushed fennel seeds and orange zest/ juice. Sprinkle the mixture over the salmon flesh. Gently press it down into the flesh. Let sit.
Wash and peel the beets. Using the largest holes on a box grater, grate the beets. Arrange on top of the salt mixture and on the sides of the salmon. Top with fresh dill. Tightly cover the salmon with remaining plastic wrap. Place on a sheet pan or baking dish. Place another baking dish or pan on top. Weigh it down evenly with cans, jars or other heavy kitchen supplies. Refrigerate for 3 days.
At day 3 you can unwrap the salmon and scrape off the mixture. Rinse gently with cold water. Pat dry with paper towels. Cut long, thin pieces on a slant, using a sharp carving knife. Leftover salmon can be well wrapped and refrigerated for 5 to 7 days.
Stir zest into crème frâiche. Stir in juice. Add scallion and salt and pepper to taste. Refrigerate until use.
Arrange artfully on the board along with the crème frâiche and accompaniments.