Season the pork shoulder with salt. Place the pork shoulder into a slow cooker and cook on low for 8-10 hours.

Meanwhile, for the fresh tomato salsa, mix all of the ingredients together in a bowl and season, to taste, with salt, freshly ground black pepper and more lime juice.

For the guacamole, mash the avocado pieces and garlic together until smooth, then stir in the lime juice and season, to taste, with salt, freshly ground black pepper and more lime juice.

To serve, remove the skin and fat from the pork shoulder and shred the meat with two forks. Place the meat into a bowl. Mix the chipotle sauce with two tablespoons of the cooking liquid and pour the mixture over the pulled pork. Mix until the pork is coated in the sauce.