Bring the rice, water, butter and 1 tablespoon olive oil to a boil in a saucepan over high heat. Reduce heat to medium-low, cover and simmer until the rice is tender and the liquid has been absorbed, 20 to 25 minutes.
Preheat an oven to 180 degrees C.
Heat 1 tablespoon of olive oil in a frypan over medium heat. Stir in the onion and garlic; cook and stir until the onion has softened and turned translucent, about 5 minutes. Stir in the tuna, cream, tomato sauce, Tabasco sauce, salt and pepper. Simmer on low until the mixture thickens, about 10 minutes.
Cover the bottom of an 23cm square baking dish with half of the cooked rice. Spread the tuna mixture over the rice and cover with the remaining rice. Sprinkle the olives and cheese over the top of the rice. Bake until the cheese melts and the casserole is heated through, 15 to 20 minutes.