To marinate the salmon, place the salmon in a deep bowl and add the ginger, garlic, scallions, salt, and pepper. Cover with sake and let stand for 1 hour in the refrigerator.
Split pineapple in 1/2 lengthwise. Cut out the woody central core from one half, then cut out and dice the sweet flesh. Set aside.
To prepare the pineapple reduction: Melt butter in small saute pan until bubbling. Add 1 tablespoon red pepper flakes, pineapple dice, and 2 tablespoons of the sake marinade. Cook down until all liquid has evaporated. Turn on grill to medium, when hot, place the salmon on the grill and cook about 3 minutes per side. Season with salt and pepper.
Put sesame oil in a hot wok or non-stick pan, add ginger, garlic, and shrimp. Be sure to keep moving the ingredients until the shrimp turn color, then add the egg, scallions, rice and soy sauce, to taste. Keep stirring everything until the oil is all absorbed. When finished put the rice in the pineapple and top it with the salmon and a small side of the pineapple reduction.