1. Cut the chicken into bite-size pieces, preferably in strips. Mix the seltzer, sugar, and salt in a bowl and add chicken. Refrigerate for half an hour or up to 12 hours. Meanwhile, combine all the ingredients for the batter in a bowl and refrigerate for half an hour hour, as well.
2. Fill a pot with oil and heat until the oil reaches a temperature of 350 degrees Fahrenheit (180 degrees Celsius). While the oil heats, place half the chicken between two paper towels and pat dry.
3. Place into the batter. Shake off excess batter one piece at a time and drop into the pot. Avoid overcrowding, or pieces may stick together.
4. Cook for about eight minutes, until chicken is cooked through, flipping gently with a fork about halfway through. Remove with a slotted spoon onto a prepared paper towel to drain. Repeat with the other half of the chicken pieces.