Remove and discard head and insides of squid, including cartilage, then rinse well under cold running water.
Use a sharp knife to open out body lengthways. Scrape out and discard membrane, then score flesh lightly in a cross-hatch pattern and cut into strips.
Combine squid, 50 ml olive oil, onion, garlic, paprika and lemon juice in a bowl and marinate for 20 minutes.
Place chickpeas in a heatproof serving bowl. Heat remaining olive oil in a frying pan over medium-high heat, add chorizo and cook, tuning once, until crisp (2-3 minutes). Add to chickpeas and return pan to heat.
Drain squid from marinade, add to pan and cook quickly until squid just turns opaque (1-2 minutes), then add to chorizo mixture.
Add marinade to pan, cook briefly until onion is tender (1-2 minutes), season to taste, then pour over squid and chorizo mixture.
Add parsley and sherry vinegar, toss to combine and serve immediately.