In a bowl, combine the cooked rice, lime juice and cilantro and salt. This can be served hot or room temperature.
For the beans:
In a small saucepan, combine the beans, cumin, garlic powder and onion powder. Season to taste with salt and pepper. Bring to a simmer and let cook for 5 minutes.
To assemble:
Lay out two serving bowl. Place layer 1 cup of rice along with 1/2 cup beans in each bowl. Divide the remaining toppings (meat, cheese, avocado, bell pepper and corn) among the two bowls.