Combine the olive oil, lime juice, garlic, brown sugar, chili powder, cumin, crushed red pepper, salt, smoked paprika, oregano and cilantro leaves in a medium bowl. Whisk to blend.
Reserve half of the marinade for later use.
Add the chicken to the remaining marinade, toss to coat, and let sit while you prepare the vegetables.
Cut the peppers and onions into thin strips and set aside.
Heat 2 large skillets over medium-high heat.
Add the chicken to one skillet and cook, stirring occasionally, until no longer pink in the center, about 5-7 minutes. Remove to a plate.
Add the olive oil and cauliflower rice to the second skillet and season with salt and pepper. Cook until tender, stirring often, about 10-15 minutes.
After removing the chicken, add the peppers, onions and 2-3 tablespoons of the reserved marinade to the same skillet and cook until just charred and fork tender, about 5-7 minutes.
Assemble the bowls with equal amounts of the cauliflower rice, chicken, and vegetables. Top with avocado, cilantro, and drizzle with reserved marinade, if desired.