Heat the oil in a large saucepan over medium heat. Add the onion and garlic, cooking until light brown, about 10 minutes.
Add the quinoa to the pan and pour the broth over it. Season with the cumin, cayenne, salt and pepper.
Bring the mixture to a boil. Then cover the pan, reduce the heat and simmer until the quinoa has absorbed all the broth, about 20 minutes.
Stir in the frozen corn and simmer about 5 minutes. Stir in the black beans and cilantro and remove from heat. Let sit for a few minutes before fluffing with a fork. Serve hot or cold.