To prepare mayo, combine first 4 ingredients in a small bowl. Cover and chill.
To prepare calamari, cut squid tubes into 1/2-inch rings. Leave tentacles intact. Rinse and pat dry.
Combine cornmeal and next 3 ingredients in a large heavy-duty zip-top plastic bag; add half of squid. Seal bag; shake to coat.
Heat 1/4 cup oil in a large skillet over high heat. Add squid coated with cornmeal mixture to hot oil; cook 2 minutes, turning frequently, or until squid begins to curl around edges. (Do not overcook.) Remove squid from pan; drain on paper towels. Repeat procedure with remaining squid, cornmeal mixture, and 1/4 cup oil. Serve immediately with garlic mayo and lemon wedges.
Calamari has a reputation for being rubbery, but it only becomes tough if it's overcooked. For pan-frying, use a skillet or sauté pan—a wide pan with sloped or straight sides. Choose a heavy-bottomed pan for evenly distributed heat with no hot spots. Also, the key when pan-frying is to make sure your oil is hot and then cook the food quickly.