Make the sauce: In a small bowl, stir together sour cream, mayonnaise, lime juice, chili powder, cumin, and a pinch of salt. Add a splash of water to reach a drizzle-friendly consistency.
Set aside.
Prep the base: Add greens to bowls. If using cauliflower rice, warm it in a skillet with a little oil and salt, then divide between bowls.
Cook the beef: Heat a large skillet over medium-high. Add oil if your beef is very lean.
Crumble in the beef and cook, breaking it up, until browned with crispy edges, about 6–8 minutes. Drain excess fat if needed.
Season it: Reduce heat to medium. Stir in chili powder, cumin, smoked paprika, garlic powder, onion powder, salt, and pepper.
Add tomato paste and 2–3 tablespoons of water or broth. Cook 1–2 minutes until the beef is coated and saucy.
Assemble: Top greens with a generous scoop of the seasoned beef. Add tomatoes, red onion, avocado, cheese, jalapeños, and cilantro.
Finish and serve: Drizzle with the creamy Southwest sauce.
Squeeze lime over the top. Taste and adjust salt or acidity if needed.