Place a pot over medium-heat heat; add oil and heat until oil shimmers slightly. Pour rice into the hot oil, stirring constantly, until rice is golden to dark brown, about 5 minutes.
Mix water, tomatoes, onion, cilantro, and bouillon into rice. Bring to a boil. Turn off heat and cover pot tightly with a lid. Leave pot covered on hot burner until rice has absorbed all the liquid, about 20 minutes. Adjust seasonings as needed.