Trim any major fat excess from the ribs. I like to leave a little on for flavor. In a bowl, whisk together the sugar, salt, pepper, paprika, garlic powder and cumin.
Rub the seasoning mixture evenly over the ribs. At this point, you can throw the short ribs directly in the slow cooker or you can brown them first. I have this slow cooker that sears meat in the crock, and it's amazing!
To sear the beef, add the oil to a large pot or dutch oven (or that slow cooker). Add the ribs and sear on all sides until golden brown, about 1 minute per side. Place the short ribs in the slow cooker and add the liquid smoke and beer. Cover and cook on low for 8 hours.
After 8 hours, remove the short ribs and shred them with kitchen tongs or a fork. Place them back into the slow cooker and cook on high for 30 minutes or so, so they soak up some of the juices.
To braise the short ribs in the oven: sear the short ribs in a cast iron or enamel (any over-safe) dutch oven as instructed above. Pour 8 ounces of beer/broth in the pot. Cover the pot and stick it in the oven. Braise for 2 1/2 to 3 hours. After 3 hours, the ribs should be tender and falling apart.