In a large, nonstick pan, cook beef and onions together over medium heat, stirring occasionally, until beef is browned and no longer pink. Be sure to break up the beef into a crumble while browning. Drain fat in sink. Stir in cooked cauliflower rice, water, salsa, beans, and taco seasoning mix. Mix well. Continue to cook 5-8 minutes to blend flavors, thicken and heat completely.