Preheat oven to 325 degree F. In a 4-quart pot arrange onion slices in bottom of pan. Sprinkle pork roast evenly with paprika. Place roast on top of onion. In a medium bowl combine undrained tomatoes, undrained chili peppers, oregano, black pepper, and salt. Pour over roast in pot. Cover and bake for 2-1/2 to 3 hours or until roast is very tender.
Remove pork to cutting board, reserving mixture in pot. Using 2 forks, pull pork into shreds. Skim fat from pan juices. Add shredded meat to pan juices; stir until combined. Heat through. Spoon pork mixture onto rolls. Makes 8 or 9 sandwiches.