Heat the olive oil in a large pot over medium heat. Add the diced onion and sauté for about 3-4 minutes until it becomes translucent.
Stir in the minced garlic and cook for another minute until fragrant.
Add the cumin and chili powder to the pot, stirring constantly for 30 seconds to toast the spices.
Add the rice to the pot and stir well to coat it in the oil and spices.
Pour in the vegetable broth, then bring everything to a boil. Once boiling, lower the heat to a simmer, cover the pot with a lid, and let it cook for about 15 minutes.
After 15 minutes, add the black beans, cover again, and continue to simmer for another 5-10 minutes, or until the rice is fully cooked and has absorbed the liquid.
Once done, remove the pot from heat, fluff the rice and beans with a fork, and season with salt and pepper to taste.
Serve warm, garnished with chopped cilantro if desired, and lime wedges on the side.