Rinse the rice under cold water. Combine rice, water, and salt in a saucepan and bring to a boil.
Reduce heat to low, cover, and simmer for 15 minutes until rice is tender and water is absorbed.
Remove from heat, keep covered for 5 minutes, then fluff the rice with a fork.
Season the chicken pieces with Cajun seasoning, salt, and pepper in a medium bowl.
Heat olive oil in a large skillet over medium-high heat. Cook chicken 5 to 7 minutes per side until golden and cooked through.
Transfer chicken to a plate and let rest for 2 minutes, then slice.
In the same skillet, heat 1 tablespoon olive oil over medium heat. Add diced bell peppers and red onion, sauté for 4 to 5 minutes until softened.
Stir in corn and black beans, cook for 2 minutes until heated through. Season with salt and pepper to taste.
Divide the cooked rice among 4 bowls, top with sautéed vegetables and beans, then sliced chicken.
Garnish with avocado slices, fresh cilantro, and lime wedges as desired.