Adobo sauce is a purée of chile peppers, herbs, and vinegar.
Process first 7 ingredients in a blender or food processor until mixture is smooth.
Cut pork in half, and place in a 5-quart slow cooker. Pour tomato mixture over pork. Cook at HIGH for 8 hours; remove from slow cooker. Cool slightly; shred and serve on buns with Rosemary-Garlic Mayonnaise and desired toppings.