Wash the goose thoroughly inside and out. Dry well with paper towels. Prick the skin with a fork or fine skewer (this helps release the fat during cooking) and generously rub all over with sea salt. Stuff the bird with the cut fruit. Tuck the wings under so they are not exposed. Add 1/2 inch water to the roasting pan and position the goose breast side down in a roasting rack. Place the pan in the oven for 45 minutes. Check the bird while it's roasting to make sure the water doesn't evaporate or the goose fat will burn. After 45 minutes, take the goose out of the oven. Turn it breast side up and prick the skin again. Carefully remove the excess fat by tilting the pan and using a baster. Add another 1/2-inch of water to the pan. Continue to roast for another 2 hours.
The goose is cooked when its juices run clear when the thigh is pierced with a skewer. If they are at all bloody, roast for a further 15 minutes and check again. To be sure the goose is cooked, insert a thermometer in the thickest part of the thigh. It should read 170 degrees F on an instant-read thermometer. Remove from the oven and let it rest for 15 minutes.
Pour out excess fat leaving about 2 tablespoons. Add the scallions, ginger, blackberries, sugar and soy sauce. Saute for 5 to 10 minutes until the blackberries begin to break up and the juices are released. Add Zinfandel and reduce by half then add the chicken stock and reduce by half again. Pass sauce through a sieve and discard the pulp. Serve with the goose.