Cut each duck into eight pieces, reserving the carcass. Sprinkle the pieces with the salt and cayenne.
Divide the marinade into two equal portions. Pour each portion into a 1-gallon plastic bag. Divide the duck pieces equally between the bags. Seal and shake the bags to coat the duck pieces evenly with the marinade. Refrigerate for 24 hours, turning the bags over several times.
Drain the duck pieces in a colander, reserving the marinade. Pour the marinade into a saucepan and simmer over medium-low heat until it is thick and dark, about 30 minutes. Set aside.
Preheat the oven to 350?F.
Heat a large saut╚ pan over high heat with no oil. Add the duck pieces, skin side down, in batches, and sear until the skin is crisp, brown, and caramelized, about 4 minutes. Turn them over and sear for about 3 minutes. Transfer the pieces to a wire rack set in a baking pan lined with parchment or waxed paper. Bake for 35 minutes. Remove from the oven and smear all the pieces with the marinade. Return the duck to the oven and bake until the juices run clear, about another 15 minutes. Serve hot.
Yield: 8 to 10 servings