Heat oil in a saucepan over medium heat. Dice pepper and onion; mince garlic.
Add veggies and garlic to hot oil. Saute for 1-2 minutes, then add quinoa, cumin, salt, pepper, cayenne pepper (if desired), and broth. Stir to combine. Bring to a boil then reduce heat, cover, and simmer for 15 minutes or until nearly all the broth has been absorbed.
Drain and rinse beans; add to quinoa along with corn. Heat through and stir in chopped cilantro.