Heat a frying pan over medium heat. Add the peppercorns, chilli flakes, five-spice powder and salt and cook, stirring, for 1 minute or until fragrant. Place the spice mixture in a small food processor and process to a rough powder. Mix half the spice mixture with the rice flour. Dip the squid in the eggwhite and toss in the spice mixture to coat. Heat the oil in a large frying pan or wok over high heat. Cook the squid, in batches, for 1 minute or until crisp. Drain on absorbent paper and toss with the remaining spice mixture. Serve with the lemon. Serves 6–8.