Cut orange skin (no white) from thick-skinned oranges. Use a very sharp knife for this job. Cut the thin skin into julienne strips. Put into a saucepan and cover with cold water. Bring to a boil, simmer 5 minutes, drain, add cold water, and drain again. (Boiling blanches the skin and removes the bitterness.)
Carefully peel the white membrane from the orange sections without tearing into the meat of the orange. Break the oranges into their natural sections.
Bring sugar, water, and salt to a boil. Cook 2 minutes. Add about 12 sections. (If oranges are large, use only 4 oranges and not 6.) Cook 5 minutes. Lift from syrup and arrange sections in wagon wheel fashion on plates. Cook the remaining sections. Cook enough orange sections to make 6 servings, or as many as you need.
When sections are cooked and on the plates, add the blanched rinds to the syrup. Cook about 5 minutes, or until skins turn a very dark orange. Remove syrup from heat. Add Grand Marnier and Cognac. Stir well and distribute candied peel over orange sections. Spoon syrup over each plate, cool, cover, and then refrigerate. Serve very cold with Sablé cookies.