Rinse the rice and shake off as much water as possible.
In a medium saucepan, heat the oil. Add the onion and garlic and sautee until soft. Add the uncooked rice, annatto, paprika, and cumin. Stir to combine.
To the rice, add the water, salt, and pepper. Bring to a boil, then lower the heat to a simmer and cover. Allow to simmer for 10 minutes.
Add the frozen peas, stirring to combine. Cover and allow to simmer for another 10 minutes, or until the water has evaporated and the rice is tender. Fluff the rice and serve.