For the taré sauce, add the sugar, mirin, soy sauce and sake to a saucepan and bring to a boil. Continue to boil until the sauce becomes thick, several minutes. Be careful to watch it so it doesn’t burn. Set aside.
Using a microplane or spice grinder, shave or pulverize the dried mushrooms into dust. Set aside.
In a food processor add the chicken, white parts of the green onion only saving the green tops for garnish, sake, potato starch, salt, liquid smoke and mushroom powder. Pulse until mixed yet still chunky, not fine like ground chicken. She into 6 oval shaped patties.
In a frying pan over medium heat add the oil and brown on each side for several minutes. Add water and cover to steam until evaporated. Brush both sides with taré sauce and cook to glaze. Internal temperature should be 160°F.
Remove from pan, insert skewers for serving and sprinkle with chopped green onion tops, powdered red pepper flakes and sesame seeds. Serve with steamed rice and vegetable of choice.