Cut the bodies of larger squid into 1/2-inch rings. Smaller squid should be fried whole. Make sure the squid have been rinsed and patted as dry as possible.
Preheat the oven to 200°. Place a wire rack on a baking sheet and set it in the oven.
Pour oil to a depth of 3 inches in a stockpot or Dutch oven, place it over medium-high heat, and heat it to 365°. Salt and pepper the squid. Place the flour in a shallow bowl.
When the oil reaches 365°, drop several pieces of squid into flour and toss to coat fully. Shake off excess flour, then fry in the hot oil until lightly browned, about 3 minutes. Using a wire-mesh strainer, transfer the squid to the wire rack. Continue frying, always maintaining the temperature and not crowding the pot. Serve immediately, with cocktail sauce for dipping, if desired.