Preheat oven to 200 degrees F.
Cut halibut in 4 equal pieces. In a mixing bowl, combine ginger, light soy sauce, white wine, and pepper in mixing bowl. Add fish to bowl and let marinate for about 20 to 30 minutes.
Defrost potato nuggets; add panko, hoisin, oyster sauce, soy sauce, rice wine vinegar, and sesame oil. Mix together thoroughly and divide into 4 equal amounts.
Heat a medium nonstick saute pan to low and add 2 tablespoons of oil.
Remove fish from marinade, shake off excess marinade, and dredge in flour on both sides.
Apply 1/4 of potato mixture to fish; press the mixture onto the top of the fish.
Add fish potato-side-down to saute pan; cook 2 portions at a time. Cook until potato mixture is lightly browned and crispy. Gently turn the fish over; cook the other side for 2 minutes. When finished, remove, place on a baking sheet and hold in the oven until the next two fillets are cooked. Repeat the process for the next two fillets.
Garnish with sesame seeds and green onions.
