Cut duck up into 10 pieces by splitting the breast and cutting each in half into 3 pieces, 2 thighs, 2 drumsticks and 2 wings. Save the liver and use it to thicken the sauce.
In an 8 to 10-quart heavy bottomed braising pan or Dutch oven, heat 6 tablespoons virgin olive oil over medium flame until smoking. Place duck pieces skin side down and cook until golden brown and most of the fat has been rendered. Cooking 4 to 6 pieces at a time, this should take 20 to 30 minutes. When done, drain pan of all but 2 tablespoons of fat and add pancetta. Cook until lightly browned and add onion, celery, carrots and fennel seeds and cook until softened, about 10 minutes. Add olives, sweet wine, tomato sauce and hot peppers and bring to a boil. Submerge duck pieces and liver and bring to a boil. Lower the heat and simmer 1/2 hour, or until duck is falling off the bone. Remove duck and liver to platter with tortiera. Using a wooden spoon, chop liver to fine mush, return to pan and season sauce with salt and pepper. Pour sauce over duck and serve.