Drain the oil from the tuna, reserve the oil and set both the tuna and oil aside.
Add about 3-4 tablespoons of the reserved oil to a deep pot or Dutch oven, then add the crushed garlic, onions and tomato. Saute for about 5-7 minutes, until the onions are translucent and the tomato cooks down (you can break up the tomato with a wooden spoon if you would like as it's cooking).
Add seasonings, saute everything for about 30 seconds, and then add the tuna. Use a wooden spoon to break the tuna apart slightly (I like to leave larger pieces of tuna in-tact).
Add the olives, bay leaf and water, and bring the pot to a boil. Add your rice, stir it and then cover the pot. Let let the rice cook over a very low flame for 20-25 minutes. Do not mix or uncover the rice while it is cooking.
After 20 minutes is up, taste the rice and if you are satisfied with the texture, turn the flame off, re-cover the pot with the lid, and let the rice rest for 5- 10 minutes. If you decide that the rice is not soft enough, let it continue to cook for another 5-10 minutes then turn the flame off and let the covered pot rest for 5-10 minutes.
Once the rice has rested, fluff it with a fork and serve.