Preheat oven to 350 degree F. Discard au jus from pork roast or reserve for another use. Cut pork into bite-size pieces (should have about 2 cups pork pieces).
In a large skillet combine pork pieces, the 16-ounce jar salsa, the beans, and dry burrito seasoning mix. Cook and stir over medium heat until heated through.
Meanwhile, wrap tortillas tightly in foil. Heat in preheated oven for 10 minutes to soften.
To assemble, place 1/2 cup of the meat mixture onto each tortilla, just below the center. Sprinkle with cheese. Fold bottom edge of each tortilla up and over filling. Fold opposite sides in and over filling. Roll up from the bottom. Secure rolled tortillas with wooden toothpicks, if necessary. Place burritos on a baking sheet, seam sides down.
Bake in the 350 degree F oven about 20 minutes or until heated through. Remove and discard toothpicks. If desired, serve with additional salsa and sour cream. Makes 10 servings.