Wash the duck under cold water, then pat dry inside and out with paper towels. Tie one end of a 20-inch length of white cord around the neck skin. If the skin has been cut away, loop the cord under the wings. Suspend the bird form the sting in a cool, airy place for 3 hours to dry the skin.
In a 12-inch wok or large flameproof casserole, combine 6 cups water, 1/4 cup honey, ginger root and cut scallions, and bring to a boil over high heat. Holding the duck by its string, lower in into the boiling liquid. With string in one hand and a spoon in the other turn the duck from side to side until all of its skin is moistened with the liquid. Remove the duck (discarding the liquid) and place it again in the cool place, setting a bowl beneath it to catch any drippings; the duck will dry in 1 hour with a fan trained upon it or 2 to 3 hours without it.
Make the sauce by combining hoisin sauce, water, sesame-seed oil and sugar in a small pan, and stirring until sugar dissolves. Bring to a boil then reduce heat to its lowest point and simmer uncovered for 3 minutes. Pour into a small bowl, cool and reserve until ready to use.
To make scallion brushes, cut scallions down to 3-inch lengths and trim off roots. Standing each scallion on end. Place scallions in ice water and refrigerate until cut parts curl into brushlike fans.
Preheat oven to 375 degrees F. Untie the duck and cut off any loose neck skin. Place duck, breast side up, on a rack and set in a roasting pan just large enough to hold the bird. Roast the duck in the middle of the oven for one hour. Then lower the heat to 300 degrees F, turn the duck on its breast and roast for 30 minutes longer. Then, raise the heat to 375 F degrees, return the duck to its original position and roast for a final half hour. Transfer the duck to a carving board.
With a small, sharp knife, remove the crisp skin from the breast, sides and back of duck. Cut skin into 2-by-3-inch rectangles and arrange them in a single layer on a heated platter. Cut the wings and drumsticks from the duck, and cut all the meat away form breast and carcass. Slice meat into pieces 2-1/2 inches long and 1/2 inch wide, and arrange them with the wings and drumsticks on another heated platter.
To serve, place the platters of duck, the heated pancakes, the bowl of sauce and the scallion brushes in the center of the table.
Traditionally, each guest spreads a pancake with it. The scallion is place in the middle of cake is folded over the scallion and duck, and tucked under. One end of the package is then folded over about 1 inch to enclose the filling, and the whole rolled into a cylinder that can be picked up with the fingers and eaten.
As a main course, Peking duck will serve 6. As part of a Chinese meal, it will serve 8 to 12. If more than six are to be served, increase the number of pancakes and scallion brushes.