Combine Beaujolais, chopped shallots, balsamic vinegar, crushed peppercorns, and crushed coriander seeds in medium saucepan. Boil until reduced to 1 1/2 cups, about 12 minutes.
Add orange juice and boil 5 minutes.
Add chicken broth and boil until reduced to 3 cups, about 15 minutes. Strain. Do ahead Sauce can be made 2 days ahead. Cover and chill.
Preheat oven to 250°F. Using sharp knife, score skin of duck breasts diagonally to create 3/4-inch-wide diamond pattern.
Sprinkle duck with salt and pepper.
Heat 1 large and 1 medium skillet over medium-high heat.
Place 2 duck breasts, skin side down, in large skillet and remaining duck breast in medium skillet. Cook until skin is brown and crisp, about 8 minutes. Turn; cook until brown and thermometer inserted into center registers 130°F for medium-rare, about 6 minutes.
Transfer to rimmed baking sheet and place in oven to keep warm.
Drain kumquats, reserving syrup.
Pour off fat from skillets, reserving 2 tablespoons fat in large skillet for sauce.
Heat large skillet with fat over medium-high heat.
Add reserved sauce and 4 1/2 tablespoons reserved kumquat syrup. Boil until sauce is thickened and reduced to 3/4 cup, about 5 minutes.
Slice duck breasts crosswise into 1/2-inch-thick slices. Divide duck breast slices among 6 plates.
Drizzle duck with red wine sauce, garnish with candied kumquats, sprinkle with crushed peppercorns, and serve.