Put diced ginger in a saucepan and cover with water. Bring to a boil and simmer for 15 minutes. Drain and repeat two times. Drain thoroughly and puree ginger in a blender until smooth and paste like; set aside. Combine wine and shallots in a heavy saucepan and bring to a boil. Simmer until only 1/2-cup wine remains. Add corn oil, a little at a time, stirring constantly. Add salt, mix well, and cover to keep warm. Remove skin from salmon and remove any little vertical bones with tweezers; cut into 4 equal portions. Spread a thin layer of the ginger puree on top of each portion and sprinkle evenly with cracked peppercorns. Heat oil in a skillet large enough for all 4 portions of salmon. When skillet is very hot, sauté the salmon, ginger-side down, for 2 minutes. Turn fish and sear other side just to seal; do not overcook. Remove fish from pan and place on paper towel, ginger-side up. To serve, spoon 2 tbsp. of the red wine sauce on each of four plates and top with the salmon.
Ready in 30 min