Place the rice flour, egg and panko in three separate shallow bowls.
Take the chicken out of the fridge.
Dredge each chicken fillet in flour and shake off the excess.
Dip the floured chicken in egg making sure every inch of the surface is moistened.
Roll the chicken fillet in panko to coat the surface completely.
Heat enough cooking oil in a wok or frying pan to reach a depth of at least two inches.
Over medium heat, fry the chicken fillets in batches for two to three minutes per side, scoop out and rest on a rack or plate lined with paper towels.
Turn up the heat to high.
Fry the chicken fillets a second time for a minute or so until browned and crisp.
Chop the fried chicken fillets into strips and arrange in a serving plate or bowl.
Drizzle the lemon sauce over the chicken and sprinkle with sliced scallions.
Serve the lemon chicken with rice.