Warm the pan. Heat a large skillet over medium-high. Add the oil and let it shimmer.
Brown the beef. Add the ground beef, breaking it up with a spatula.
Season lightly with salt and pepper. Cook until browned and no longer pink, about 5–7 minutes. Drain excess fat if needed.
Sweat the aromatics. Push the beef to one side.
Add onion and bell peppers to the open space. Cook 3–4 minutes until softened. Stir in the garlic and cook 30 seconds until fragrant.
Season it right. Sprinkle the taco seasoning over everything.
Stir well so the spices coat the meat and veggies.
Add tomatoes and paste. Stir in the diced tomatoes and tomato paste. Let it simmer 3–4 minutes to thicken and concentrate the flavor.
Cook the cauliflower rice. Add the cauliflower rice to the skillet. Stir well to combine.
Cook 5–7 minutes, stirring occasionally, until tender and most of the moisture cooks off. Taste and adjust salt and pepper.
Finish with cheese. Reduce heat to low. Sprinkle cheese over the top.
Cover and let it melt for 1–2 minutes.
Garnish and serve. Turn off the heat. Top with cilantro and a squeeze of lime. Serve straight from the skillet with your favorite toppings.