Liberally sprinkle salt over fish, and leave for 15 minutes. Remove any moisture from the fish with a paper towel. Cut fillets into 5-6 pieces each and coat lightly in Katakuriko.
Slice onion very thinly. Cut carrot into thin matchsticks. Slice green onions thinly and diagonally. Put all the vegetables together in a glass dish or other heat-proof medium-deep container.
In a pot, mix rice vinegar, Dashi, sugar, Soy Sauce, Mirin, Sake, and chili pods. Cook to a boil and remove from heat. Pour the hot sauce over vegetables.
Deep fry the fish at 350F (180C) for 3-5 minutes. Immediately add to the vinegar sauce, and coat with the sauce.