1 1/4 pounds boneless chicken thighs
3 tablespoons soy sauce
1 tablespoon rice vinegar
2 teaspoons finely grated ginger
2 teaspoons finely grated garlic
1/2 cup potato starch or cornstarch
1/3 cup all-purpose flour
Corn or canola oil for deep frying
Japanese mayonnaise (Kewpie brand) or lemon wedges for garnish
1. Cut the chicken thighs into 3-by-1-inch pieces. You should have about 36 small pieces, about half an ounce each.
2. Stir together the soy, rice vinegar, ginger and garlic, and marinate the chicken pieces for at least 30 minutes or for as long as 4 hours.
3. In a deep fryer or a deep cast-iron skillet over medium-high heat, heat enough oil to make a 2-inch-deep layer until a 1-inch cube of bread sizzles in the oil and turns golden brown in 1 minute. A candy thermometer will register 365 degrees. Preheat the oven to 250 degrees and put a cooling rack on top of a sheet pan to receive the chicken strips as they are fried. Keep the cooling rack and the sheet pan in the oven.
4. Combine the potato starch and flour, then dip the chicken strips, six or eight at a time, in the starch mixture; shake off the excess and fry the chicken pieces without crowding until they are chestnut brown and cooked through, about 5 minutes. Hold the first batches on the rack in the oven while subsequent batches are fried. Impale each piece of chicken on a small wooden skewer if desired. Serve with the mayonnaise or lemon wedges, if desired.