Combine brown rice and water in a saucepan; bring to a boil, then cover and simmer on low heat for 25 minutes until water is absorbed.
In a small skillet, heat black beans with ground cumin and chili powder over medium heat for 5 minutes until warmed through.
In a small mixing bowl, combine cherry tomatoes, diced red onion, and 2 tablespoons of chopped cilantro with 1 tablespoon of lime juice.
Assemble the bowls by distributing the cooked brown rice evenly among four serving containers.
Top the rice with equal portions of the seasoned black beans, corn, tomato-onion salsa, and avocado slices.
Garnish with the remaining cilantro and a final drizzle of lime juice.