Rub the salt all over the roast. Let it sit while you assemble the spice paste.
Slice the chipotle peppers in half, scraping out the seeds. (Leave them in if you want to add a big kick of heat.) Chop the peppers and put them in a small bowl with the adobo sauce, garlic, juice from 1 lime, cumin, chili powder, oregano, black pepper, and cloves. Stir well and rub the paste all over the roast.
Place the roast in a 4-7 qt slow cooker along with the bay leaves, onions, and tomatoes along the sides or on top.
Cover and cook on low for 8-10 hours or until the meat pulls apart easily with a fork.
Shred the roast on a large platter and return the meat to the pot with the juices. Stir in the fresh cilantro. Taste, and add more salt and lime juice if necessary.
