Cut the chicken into bite sized pieces. Combine potato starch, garlic powder and salt in a small bowl. Toss the chicken in the dry mixture until it is coated. Cover and refrigerate for at least 1 hour (up to overnight).
Heat 3/4" of vegetable oil in a heavy bottomed pan. If you have a food thermometer, aim for an oil temperature of 175 degrees. If not, set the burner to medium heat.
Drop the chicken pieces into the oil and fry until slightly browned, about 8-10 minutes. Remove with a slotted spoon onto a paper towel-lined plate. Wait 1-2 minutes, then put the chicken back into the oil for an additional 2-3 minutes, until golden brown. Remove onto paper towels again.
Combine all of the Hawaiian sauce ingredients in a large bowl. Toss the hot chicken in the sauce.