In a large skillet over medium heat, cook the lean ground beef and minced onion, breaking up the meat, until beef is browned and onion softens, about 6-8 minutes. Add minced garlic and sauté for another minute until fragrant.
Sprinkle taco seasoning over the beef mixture and stir to coat evenly. Pour in water, reduce heat to low, and simmer gently until liquid thickens and flavors meld, about 5 minutes. Remove from heat and set aside.
Lay one burrito-size flour tortilla flat. Spread about 2 tablespoons of nacho cheese sauce in the center, leaving edges clear. Place a tostada shell on top of the sauce, then spoon 1/6 of the seasoned beef over the tostada.
Add a dollop of sour cream on top of the beef, then layer shredded lettuce, diced tomatoes, and a sprinkle of Mexican cheese blend. Add salsa or pico de gallo and scatter fresh cilantro if desired.
Carefully fold the edges of the tortilla up and over the filling, pleating as needed to create a sealed circular wrap. Ensure filling is enclosed to avoid spills during cooking.
Heat a non-stick pan or griddle over medium heat. Place the folded Crunchwrap seam-side down and cook for 2-3 minutes until golden and crisp. Flip and toast the other side until golden and cheese melts, another 2-3 minutes.
Remove Crunchwrap Supreme from pan and let rest briefly before slicing in half. Serve warm with extra salsa, sour cream, or your favorite sides.