Place beef in a Dutch oven over medium heat. Pour in water. Cover, and cook for 30 minutes. Remove cover, and cook until liquid has evaporated, and beef is well browned, about 10 minutes. In a medium bowl, combine beef broth, red wine vinegar, chili powder and cumin. Pour over beef. Cover, and cook until meat is very tender, and pulls apart easily, about 2 hours. Allow to cool, then shred and mix with pan juices.
Preheat oven to 500 degrees F (260 degrees C).
Brush both sides of each tortilla with melted butter. Spoon shredded beef filling down center of each tortilla. Fold ends over filling, then fold sides to center to make a packet. Place chimichangas, seam side down, in a 9- by 13-inch baking pan.
Bake in preheated oven for 8 to 10 minutes, or until golden brown. Serve with shredded cheese, sour cream and salsa.
