Cut roast in half. Combine the salt, oregano, cumin, paprika and pepper; rub over pork. Place in a 4- or 5-qt. slow cooker.
Mince cilantro to measure 1/4 cup; set aside. Trim remaining cilantro, discarding stems. Add the whole cilantro leaves, onions, chiles and garlic to the slow cooker. Combine the broth, orange juice and lime juice; pour over roast. Cover and cook on low for 7-9 hours or until meat is tender.
Remove roast; cool slightly. Skim fat from cooking juices; set aside 3 cups juices. Discard remaining juices. Shred pork with 2 forks and return to slow cooker. Stir in minced cilantro and reserved cooking juices; heat through. Spoon 1/2 cup meat onto each bun. Serve with barbecue sauce and pickle chips.