Preheat the oven to 450 degrees and arrange the oven rack so it is positioned in the center of the oven.
Remove the innards and reserve them for another recipe, if desired. Remove any pockes of fat surround the duck cavity. Then season the inside ofthe duck with salt.
In a pot large enough to hold the duck, combine the water, 3/4 cup of the soy sauce and 1/3 cup of the honey. Bring the mixture to a simmer. Lower the heat and submerge the duck. Let it simmer for 30 seconds and turn it on its opposite side. Remove the duck, place it on a baking sheet and allow it to dry. Ideally, the duck should sit overnight to allow the flavors to meld with the duck and for the skin to dry out. This will mean a crisper skin once the duck is cooked.
Count about 15 minutes roasting time for each pound of duck. Place the duck in a roasting pan fitted with a rack that elevates it off the bottom of the pan. The rack will allow hot air to circulate around it as it cooks. Place the onions in the bottom of the pan.
In a medium pot, combine the green peppercorns, brine and Champagne vinegar with the remaining soy sauce and honey and bring to a boil. Lower the heat and simmer gently, allowing to reduce and the flavors to blend. Taste for seasoning. Allow it to cook until all the flavors meld together.
Place the duck in the center of the oven and cook, undisturbed, for half an hour. Then increase the oven temperature to 400 degrees. Remove the duck from the oven and baste with the drippings in the bottom of the pan. Season the outside with salt. Return the pan to the oven and cook for an additional 5-10 minutes. The duck should register about 145 degrees when a thermometer is inserted into the thigh meat. Remove from the oven, trasnfer it to a platter and pour the glaze over the breast and thigh meat. Remove the onions and set them aside as a side dish or serve them with cooked lentils. Allow the bird to "rest" for about 15 minutes before serving.
Note: Reserve any fat that has accumulated at the bottom of the pan. I use that duck fat like oil or butter for cooking. It's delicious!