Rinse the fish under cold water and pat dry. Add the fish to a non-reactive dish just large enough to hold the steaks in a single layer.
In a small bowl, stir together the yuzu juice, saké, soy sauce, mirin, and sugar and then pour over the fish. Marinate the fish for 30 minutes, flip, and marinate for 30 minutes more.
In a small bowl, combine the ginger, garlic, lime zest, lime juice, yuzu juice, honey, and 3 Tbsp olive oil. Season with 1 tsp salt and 1/2 tsp pepper.
Remove the fish from the marinade and pat dry with paper towels. Season both sides of the fish with 2 tsp kosher salt and 1 tsp pepper, divided among the steaks.
Heat a large cast-iron skillet over high heat until very hot. Add 2 Tbsp of grapeseed oil and two of the steaks. Cook until deeply seared, about 1 minute.
Flip the steaks and cook until the internal temperature reaches 110 (rare), about 1 minute longer. Transfer to a plate and repeat with the remaining steaks, adding more grapeseed oil as needed.
Transfer the fish to a serving platter, spoon the ginger-citrus mixture all over and sprinkle with the green onions. Serve warm.