Cook the meat: Heat oil over high heat. Add ground beef, season with salt, pepper, paprika, cumin, chili flakes. Cook, breaking up the meat with a wooden spoon, until no longer pink. Turn the heat off and set aside.
Make nacho cheese sauce (or use store bought): in a saucepan melt the butter, add flour and whisk until smooth paste forms. Add the milk to the pan, turn to high heat and bring to a boil, while whisking constantly, until thickens. Add pinch of salt and cayenne pepper and whisk. Turn the heat off, add the cheese and whisk until melted and smooth.
Assembly: Lay a large tortilla on a flat surface. Add ¼ cup ground beef to the center of each tortilla. Top with cheese sauce. Add tostada shell, sour cream, lettuce, tomato, and some shredded cheese. Place smaller flour tortilla on top and tightly fold edges of large tortilla toward the center.
Cook the crunchwrap: heat the crunchwrap, sealed side down, in a pan over medium-high heat, until golden brown. Flip and cook the other side until golden brown.
