In a small bowl, whisk together chili powder, cumin, garlic powder, onion powder, salt, and black pepper.
Toss the sliced flank steak with half of the spice mixture.
Heat 1 tablespoon of olive oil in a large skillet over medium-high heat.
Add the steak to the skillet in a single layer and sear for 3 minutes per side until browned, then remove from skillet.
Add the remaining 1 tablespoon of olive oil to the same skillet.
Add bell peppers and onions to the skillet, sprinkling with the remaining spice mixture, and sauté for 6 minutes until tender-crisp.
Divide the steamed cauliflower rice among four serving bowls.
Layer the sautéed vegetables and the cooked steak over the cauliflower rice.
Garnish each bowl with sliced avocado, fresh cilantro, and a lime wedge before serving.