In a small bowl, whisk together chili powder, cumin, garlic powder, salt, and black pepper.
Toss the sliced flank steak with half of the spice mixture until evenly coated.
Heat olive oil in a large cast-iron skillet over medium-high heat until shimmering.
Add steak slices in a single layer and sear for 3 minutes until browned, then remove steak from skillet and set aside.
Add bell peppers and onions to the same skillet and sauté for 6 minutes until tender-crisp and slightly charred.
Return steak to the skillet, add the remaining spice mixture, and toss for 1 minute to incorporate flavors.
Divide steamed cauliflower rice between two bowls and top with the steak and vegetable mixture.
Garnish with chopped cilantro and serve with lime wedges.