Pat the chicken breast dry and season both sides evenly with ground cumin, chili powder, sea salt, and black pepper.
Heat the olive oil in a medium skillet over medium-high heat until shimmering.
Add the chicken to the skillet and cook for 5-7 minutes per side, or until the internal temperature reaches 165°F and the exterior is golden brown.
Remove the chicken from the pan and let it rest for 3 minutes before slicing into bite-sized strips.
In the same skillet, add the chopped red bell pepper and red onion, sautéing for 3-4 minutes until they are tender-crisp and slightly charred.
Warm the cooked brown rice and rinsed black beans in a small pot or microwave until heated through.
Assemble the bowl by placing the brown rice at the base, then topping with the black beans, sautéed vegetables, and sliced chicken.
Garnish the bowl with the avocado slice, fresh cilantro, lime juice, and salsa before serving.