In a large, heavy saucepan over medium heat, combine the cranberry sauce and 1/2 cup water. Cook until the sauce dissolves. Increase the heat to a boil and cook, stirring occasionally, until it becomes syrupy and deep amber color; about 8 minutes. Add the broth, and Sichuan peppercorns. Boil until the sauce is reduced to 1 1/2 cups; about 10 minutes. Remove from the heat and let cool. Strain and discard the peppercorns; transfer to bowl. Whisk in the rosemary and vinegar. Season to taste with generous amount of coarse salt and pepper. Cover and refrigerate until ready to use (may be stored in the refrigerator for one week). Rewarm over low heat before using. Heat oven to 400°F. Score the duck skin (be careful not to cut through to the flesh) with 5 cuts in 1 direction; repeat in opposite direction, making a diamond pattern. Generously season the duck on both sides with salt, pepper, and ground coriander. Place a large cast iron skillet over medium-high heat. Add duck, skin side down to the skillet. Cook the duck, without moving it, until skin is crisp and deep brown; about 6 minutes. Turn the duck over; cook 1 minute. Carefully pour off fat into a heatproof container. Transfer the skillet to the oven. Cook the duck until cooked to medium rare (135° on an instant read thermometer); about 5 minutes. Transfer the duck to a cutting board. Let rest it 5 minutes. Thinly slice each breast crosswise on slight diagonal. Arrange the slices on plates. Spoon sauce over. Garnish with pistachios. Recipe courtesy of Chef Will Gilson from the Cranberry Chef Collective.