Rinse the rice under cold water until the water runs clear.
In a medium saucepan, bring the vegetable broth (or water) to a boil. Add the rinsed rice, reduce the heat to low, cover, and simmer for about 30 minutes or until the rice is tender and cooked through.
Meanwhile, heat the olive oil in a large skillet over medium heat.
Add the diced onion to the skillet and sauté for about 5 minutes until softened.
Stir in the minced garlic, ground cumin, and chili powder. Cook for an additional 1-2 minutes until fragrant.
Add the rinsed black beans to the skillet, stirring well to combine with the onion and spices. Cook for another 5 minutes until the beans are heated through. Season with salt and pepper to taste.
Once the rice is finished cooking, fluff it with a fork and then combine it with the bean mixture in the skillet. Stir until everything is evenly mixed.
Serve hot, garnished with fresh cilantro and lime wedges if desired.