Season the salmon with salt and pepper. Dredge the salmon in the sugar, coating well. Heat a small saute pan, over medium heat. When the pan is hot, add the salmon, and sear for 2 to 3 minutes on each side, until the salmon is caramelized on both sides. Remove from the pan and cool completely. Flake the salmon into small pieces.
Place the egg yolks in a mixing bowl and the whites on a serving plate. Season the whites with salt. With a fork, mash the egg yolks. Add the salmon, mayonnaise, shallots, and lemon juice. Mix well. Season with salt and pepper. Fill the egg whites with the salmon mixture. Cover with plastic wrap and chill completely. Remove and garnish with caviar.