Position a rack in the center of the oven and heat the oven to 425°F. Trim any excess skin and fat from the duck and score the remaining skin and fat underneath in a 1-inch diamond pattern, taking care not to cut the flesh. Pat the duck dry and season generously with salt and pepper.
Heat a 12-inch heavy-duty skillet over medium-high heat. Put the duck in the skillet skin side down, reduce the heat to medium low, and render the fat until only a thin, crisp layer of skin remains, about 8 minutes.
Meanwhile, in a small bowl, combine the preserves, soy sauce, five-spice powder, and red pepper flakes.
Turn the duck over, carefully spoon off most of the fat from the skillet, and brush the preserves mixture over the breasts.
Transfer the skillet to the oven and roast until an instant-read thermometer inserted into the thickest part of a breast registers 135°F for medium rare, 8 to 10 minutes. Transfer the duck to a cutting board and let rest for 5 minutes. Meanwhile, tilt the skillet and spoon off as much fat from the pan juice as possible. Slice the duck diagonally into 1/4-inch slices. Arrange on plates and spoon the pan juice over. Sprinkle with the scallions and serve.