How to Make It
In a small glass or stainless-steel bowl, combine the sake, soy sauce, sesame oil, garlic, ginger, 1 tablespoon of the chives, the sugar, red-pepper flakes, and black pepper. Put the salmon steaks, in one layer, in a shallow Pyrex dish and pour the soy mixture over it.
In a large pot, bring about 1 inch of water to a boil over high heat. Put the dish with the fish and sauce in a large steamer basket. Put the basket over the boiling water and cover. Reduce the heat to moderately high and cook until the salmon is just barely done (the fish should still be translucent in the center), about 10 minutes. Serve the salmon steaks with the cooking juices poured over them and the remaining 1 tablespoon chives sprinkled on top.
As an alternative you can use firm white fish fillets such as red snapper, grouper, or sea bass. Cook them until the center is opaque.