Rub pork with 2 teaspoons salt. In 10-inch skillet, heat 1 tablespoon oil over medium-high heat. Cook pork in oil 6 to 10 minutes or until brown on all sides.
Spray 3 1/2- to 4-quart slow cooker with cooking spray. Place pork and drippings in slow cooker. Sprinkle with onion. Pour cooking sauce and beer over pork. Cover; cook on Low heat setting 8 to 10 hours.
Remove pork from slow cooker; reserve 1/2 to 3/4 cup juices. Use 2 forks to pull pork into shreds; mix pork and desired amount of reserved hot juices. Spoon into buns.