Cut each squid tube in half. Lay flat, inside up, and use a sharp knife to gently score a cross. Cut into bite-sized pieces, then pat dry with kitchen paper.
Mix together the crushed peppercorns, chilli flakes, salt and flour. Toss the squid in the mixture.
Fill a large, deep saucepan one-third full with oil and heat until a cube of bread browns in 15 seconds. Shake off the excess flour from a handful of squid and deep-fry for 2–3 minutes until just golden and crisp. Drain on kitchen paper. Keep warm in a low oven. Repeat with the remaining squid.
Deep-fry the spring onions and chilli strips for 1–2 minutes, and use to garnish the squid. Serve with lemon wedges for squeezing over.