For the wasabi tartar sauce, make a mayonnaise: In a large bowl, whisk the egg yolks, lemon juice, vinegar and mustard. Whisk in the oil in a steady, thin stream until emulsified. Season with sea salt to taste. (Alternatively, use 1 cup store-bought mayo.) Stir in the ponzu sauce (or tamari) and lime juice; mix well. Add wasabi and relish to taste.
Season the fish liberally on both sides. Place the flour in a medium dish; beat the eggs and a splash of water in a second medium dish; and combine the panko with the chives, ginger and garlic in a third medium dish. Coat the fish evenly in flour, then egg, then panko mixture.
In a large skillet, heat a shallow layer of oil, about 1/4 inch, over medium to medium-high heat. Fry the fish until golden, about 3 minutes on each side. Transfer to a paper towel-lined plate to drain and squeeze a wedge of lime or lemon over the fish.