In a large skillet, over medium-high, heat 1 tablespoon of olive oil add the sliced onions, sauté for 2-3 minutes. Add the sliced peppers and minced garlic, salt, and black pepper, and sauté for another 2-3 minutes or until the vegetables are softened. Remove from skillet, place in a small bowl, and set aside.
Over medium-high heat, add the remaining 2 tablespoons of oil to the skillet then add chicken. Cook for 5 minutes or until the chicken is fully cooked.
Add the salsa, oregano, cumin, and salt, and stir to combine. Add the black beans, corn, and reserved cooked peppers and onions. Turn heat to low and let simmer for 5 minutes.
While the chicken mixture is simmering, combine the cooked rice and cilantro in a bowl.
Turn the heat off, add spinach, and stir to combine.
To serve, add the cilantro rice to the bottom of each bowl and top with the chicken mixture. Garnish with sliced green onions and a wedge of lime.