Whole squid are easy to clean and prepare. Depending on the size the smaller are easier while the larger may take a little more time and preparation. Pull the tentacles and head from the main body (innards should come out with tentacles). You can remove the skin from the smaller squid or calamari (both of the same family) though it is recommended to remove the skin on all squid as it may be extremely chewy and undesirable. For the larger squid it is suggested by some to either soak it in buttermilk, pawpaw or even kiwi fruit. These all have active enzymes that can tenderize proteins and have been found not to impart any consequential flavour.
Remove the centre cartilage which is clear, thin and plastic like (this is inedible). I find the best way is to score it in a crisscross pattern on the inside of the body because as it cooks it curls, tenderises and if done with a little care it is also attractive. It is great sautéed marinated in garlic, ginger or whatever your preferred flavour such as chili etcetera and sautéed in light olive oil. Or slightly dusted with cornflour and flavouring of your choice, deep or shallow fried.
Tentacles take a little bit more time to prepare as the suction cups have a little circular bone like attachments that can be removed by rubbing. Remove the beak and you may also even keep or discard the ink sac. If it is still intact this may be used for making squid ink pasta or risotto. Then after cleaning the tentacles cut into desired length up to 2 inches (5 centimetres) and coat these with cornflour, salt, pepper (to taste) or my favourite is salt, pepper and chili powder quickly flash fried for a nice tasty drinking snack. Or maybe marinated in olive oil garlic and flavourings of your choosing including herbs and this acts as a nice accompaniment on any antipasto or seafood lovers plate.