In a large bowl, combine calamari, lemon juice, zest, olive oil, minced garlic, kosher salt, black pepper, red pepper flakes to taste, and oregano. Set aside to marinate for 5-10 minutes.
1.5 pounds calamari, 1 large lemon, juice and zest, 2 tablespoons olive oil, 4 cloves garlic, 2 teaspoons kosher salt, 1.5 teaspoons oregano, ¾ teaspoon coarse ground black pepper, ½ teaspoon red pepper flakes