Rinse your rice and place in a bowl and cover with water. Set aside.
Rinse and drain the calamari well, then season with salt and pepper.
Heat the 1/4 cup olive oil in a large skillet and fry the calamari over medium-high heat until cooked through. This will take approximately 3 minutes. With a slotted spoon or spatula remove the calamari from the frying pan and set aside in a bowl. You will notice that there is some liquid in the frying pan which has been released by the calamari. Pour all of this liquid into a measuring cup and set aside.
Heat 1 tablespoon of olive oil in the same frying pan and add the chopped onion, garlic and dry oregano. Cook over medium heat, stirring constantly, for 3 - 5 minutes.
Drain your rice and add it to the frying pan. Cook for a few minutes until opaque. Meanwhile, take the reserved liquid which you saved after frying the calamari and measure it out. Then, add enough water to reach 2 cups. Pour this into the frying pan with the rice and then add the tomato sauce. Stir well.
Cover the frying pan and cook over low heat for approximately 15 - 20 minutes. Check on your rice every 5 minutes to be sure that there is still enough liquid in the pan. If it appears too dry simply add more water, 1/4 cup at a time.
After 15 - 20 minutes check the rice for doneness. When the rice is cooked, add the calamari and parsley, or basil to the pan; stir well. Cook, covered, for an additional 3 - 5 minutes so that the calamari is heated through.
Before serving, add the juice of 1/2 lemon to the pan. Stir to combine.