Open the squid out and pat dry with kitchen paper. Lay them on a chopping board, shiny-side down, and, using a sharp knife, lightly score a fine diamond pattern on the flesh, being careful not to cut all the way through. Place the squid in a non-metallic bowl along with the oil, cumin, lemon rind, half the lemon juice and a little pepper (no salt at this stage). Leave in the refrigerator to marinate for at least 30 minutes, but better still overnight.
Heat a frying pan until it is very hot. Add the squid to the pan in batches, scored-side down, and cook for about 1–2 minutes, or until it turns white and loses its transparency. Remove from the pan and keep warm while cooking the rest of the squid.
Return the pan to the heat and deglaze the pan with the wine. Allow the wine to boil for a minute to burn off the alcohol. Remove the pan from the heat and add the remaining lemon juice and finally the capers. Season the squid with salt and pepper and serve with the pan juices poured over.