Start by preparing the rice. In a pan put the olive oil and chopped garlic. add the rice and let it fry for 2 minutes.
Add two cups of hot water and salt to the rice. Let it cook on low heat for 8 minutes and set aside, the rice will finish cooking in the oven.
While the rice cooks, prepare the filling. In a frying pan put the olive oil and chopped onion finely. When the onion is translucent, add the chopped garlic.
Add the chopped tomatoes and half a cup of water. Season with salt and pepper to taste and let it cook for about 5 minutes. Add the tuna and cook for another 5 minutes.
On a platter put half the rice. Place the tuna filling over the rice and cover with the remaining rice. Bake in the oven for about 15 minutes.