In a large (5- or 6-quart) pot or Dutch oven, heat the olive oil over medium heat. Add the onion, sprinkle with ¼ teaspoon salt, and cook until softened, stirring occasionally, about 3-4 minutes.
Add the garlic, tomato paste, chili powder, and oregano. Cook until fragrant, about 1 minute, stirring constantly.
Add the stock and bring to a rapid boil. Add the beans, rice and remaining 1 ½ teaspoons of salt, stirring to combine.
Cover, reduce to a low simmer, and cook for 15-18 minutes, or until the rice is just tender.
Remove the pot from the heat and allow it to sit for an additional 5 minutes. Uncover, add the lime juice, and fluff with a fork.
Serve with optional toppings, if desired.
