Cook quinoa or rice according the package instructions.
While the quinoa or rice is cooking, put the olive oil into another sauce pan on medium heat.
Add onion into the saucepan and sauté until it is browned and tender. Add the minced garlic and let it sauté for 1-2 minutes longer.
Add the black beans to the pot of onions with 1/2 cup water, 2 tbsp cilantro, chili powder, and cayenne pepper.
Once the beans start to boil, reduce heat to medium-low. Let it simmer for 15 minutes or until the liquid is mostly evaporated. Add the lime juice and season with salt to taste.
When the quinoa is entirely cooked, remove from heat and fluff with a fork.
Mix in 2 tbsp of chopped cilantro and 2 tbsp fresh lime juice. Season with salt to taste.
Pour the quinoa evenly between four bowls.
Top each portion of quinoa with 1/4 cup of shredded lettuce and simmered black beans, and add any other toppings you'd like!