Rinse the rice several times, until the water runs clear.
Heat the vegetable oil in saucepan on medium heat. Add mashed garlic. Cook for 1 minute.
Add chopped onion and tomato and cook, stirring until softened, about 3 minutes. Add water and salt and bring to a boil.
Add the rice. Lower heat to low, cover, and simmer for 15 minutes.
Turn off the heat and leave rice covered for 5 minutes more or until rice is tender. Check for seasoning. Fluff with fork and serve.