Set up Nomiku water bath and turn temperature to 64ºC (147.2ºF).
Seal wings with vacuum machine with salt according to instructions or into two-gallon size zip bags, 1 pound per bag, dividing salt equally. Seal using the water displacement method to seal zip bags and sous vide wings for 2 hours.
In the meantime, boil fish sauce until it’s reduced almost by half, stir in sugar and whisk in crab paste and 1 Tbsp of water until smooth. Reduce heat to low.
Fit a large pot with a thermometer and pour in oil. Heat till 350ºF.
In a medium bowl whisk flour, baking powder, and 1 cup cornstarch together and slowly whisk in sake and 1 cup water.
Place remaining ½ cup cornstarch in a shallow dish.
Remove chicken from water bath and drain jus. Keep for later use. Pat dry chicken. Season chicken with salt, pepper, and cornstarch. Coat chicken in batter and place in oil and fry until skin is golden. 2-3 minutes.
Place mochi blocks on greased waffle iron and close. Remove when crunchy on the outside, around 3 minutes.