Langostino, also called langoustine, are shellfish related to lobster and prawns. The meat in their tails is considered a delicacy; their heads and thoraxes are inedible. Langostino spoil very quickly, so they are usually cooked by the fishermen who catch them and frozen before they reach shore. If you are able to find fresh langostino that require cooking, cook them whole and discard the upper parts of the crustacean afterwards. Alternatively, remove the heads before cooking and use them to flavor sauces, butters and broths.
Boil
Bring a pot of salted water to a boil. Add the langostino, preferably live, and boil them for two minutes.
Submerge the langostino in cold water for four minutes to cool them and prevent them from overcooking. Snap off the inedible upper bodies, and peel the softened shells from the tails with your fingers. Throw away the heads and thoraxes.
Season the tails with lemon juice, salt, garlic butter or vinegar. Refrigerate them or serve immediately.
Grill
Grill fresh langostino briefly. Cook the first side for one minute and the second side for 30 seconds.
Submerge the cooked crustaceans in cold water for four minutes. Break off the upper parts of the shellfish, peel the tails, and discard the shells, heads and thoraxes.
Season with lemon juice, sweet-and-sour sauce or mayonnaise. Refrigerate or serve.
Saute
Cut off the upper parts of langostino using kitchen shears and set the inedible parts aside. Turn the tails upside-down, and use the shears to remove the shells, beginning at the top and moving toward the thin bottom section. Leave the shells on the final subdivision, where the tails are thinnest, to stop the flesh from overcooking and toughening.
Season the tails as desired, and saute them lightly for one minute on each side. Remove the final section of shell. Discard the peeled shells.
Cook the heads into sauces or broths for flavor, then fish them out and discard them before serving the sauce or broth. Refrigerate or serve the tails.