1. Half-fill a large saucepan with oil, heat on medium until the temperature reaches 180°C on a cooking thermometer.
2. Make the lime mayonnaise by combining the mayonnaise, lime zest, juice and kaffir lime leaves in a small bowl. Set aside.
3. Create the spice mix by placing the five spice, chilli, salt and rice flour in a medium bowl and mix to combine.
4. Place the egg whites in a separate medium bowl and whisk until slightly foamy. In batches, dip the fish in the egg white then place in the flour mixture, tossing to coat. Once coated, fry the fish in the oil. Cook pieces for 1–2 minutes or until golden brown. Remove using a slotted spoon and place on a wire rack to drain.
5. Serve with the lime mayonnaise and lime wedges.