In a large 12 inch skillet set over medium heat, heat the oil until hot. Add the beef, onion, garlic, Italian seasoning, salt, pepper, and red pepper flakes. Cook, breaking up any clumps with the back of a wooden spoon, until the beef is nicely browned.
Stir in the cauliflower rice, chopped peppers, diced tomatoes, tomato paste, and water until well combined. Bring to a simmer, then reduce the heat to medium low and cook until the vegetables are tender, about 10 minutes.
Sprinkle the cheese evenly over the skillet and cover with a lid. Cook 3 to 4 minutes more, until the cheese is melted.