Combine tomato sauce, raisins, chili powder, chipotle, and garlic in a slow cooker.
Slice the pork roast crosswise into 4 equal pieces and season generously with salt and pepper.
Place it inside the slow cooker, cover, and cook until tender, 9 to 10 hours on Low or 6 to 7 hours on High setting.
Transfer the roast to a bowl and let cool slightly. Shred into bite-sized pieces, discarding excess fat.
Using a large spoon, skim excess fat from the surface of mole sauce.
Transfer sauce to a blender and process until smooth, about 1 minute. Stir in cilantro and lime juice. Season with salt and pepper to taste, and adjust consistency with hot water as needed. Pour and mix about 2 cups of sauce with the shredded pork.
Serve with warm tortillas, remaining sauce, and any additional toppings.