Cut the pork into 4 equal sized pieces. Cut off any large pieces of fat. Heat the oil in a large skillet over high heat. Add the pork (working in batches if necessary) and brown on all sides. Transfer to a slow cooker.
Pour the enchilada sauce over the pork, then sprinkle on the brown sugar and the liquid smoke. Cover and cook for 4-5 hours on high or 8 hours on low.
Preheat the oven to 425ºF. Line a baking sheet with foil.
Once cooked, remove the pork to a cutting board. When cool enough to handle, shred with 2 forks. Using a spoon or a ladle, try to skim off as much fat as possible from the liquid left in the slow cooker. Add the shredded pork to the liquid and stir to coat.
Cover the tortillas with damp paper towels and microwave on high for 30 seconds to warm up the tortillas. Use a slotted spoon to remove some of the pork from the slow cooker and place down the center of the tortilla. Sprinkle on some of the queso fresco. Roll the tortilla around the filling then place on the prepared baking sheet. Repeat with the remaining tortillas and filling.
Spray the tops of the taquitos with nonstick cooking spray, then sprinkle on kosher salt.
Bake until the ends are golden brown, about 15 minutes.
While the taquitos are cooking, combine the mayonnaise, sour cream, avocado, chipotles, garlic, seasoning and cilantro in a food processor. Process until smooth.
Serve the baked taquitos with the Creamy Chipotle Avocado Sauce.