For the carnitas:

1. Preheat the oven to 400 degrees F. Place the garlic cloves, onion, thyme, oregano, salt, and half a cup of water in a blender and blend until smooth. Place the pork and the bay leaves in a large dutch oven or oven-safe pot with a lid, and pour the garlic and onion mixture on top of the pork. Add the coke and use tongs to toss the mixture a few times to make sure everything is well coated.
2. Cover the pot and place in the oven. Cook until the pork is so tender that it falls apart when you press it with a fork, about 2 to 2 1/2 hours. When it is very tender, remove the lid. Use tongs to stir the pork and make sure a few pieces are above the liquid line. Return to the oven for 15 minutes, browning the exposed pork. Repeat the process once more, bringing new pieces of pork above the liquid and browning those for 15 minutes.
3. Once you have browned the pork, use tongs to transfer the pieces of pork to a glass bowl or storage container. Let the remaining fat and juices left in the pan cool and solidify, then discard. Coarsely shred the pork meat with a fork. Refrigerate the pork overnight, allowing the flavors to intensify.

For the tortas:

1. Cut the telera rolls in half as you would a hamburger bun. Spread the cut side of each half lightly with butter. Heat a large frying pan over medium heat and toast the telera halves in the pan, butter side down, until golden brown. Do this in batches to prevent overcrowding the pan.
2. Once the buns are toasted, add the shredded carnitas to the frying pan in a single layer (you will likely need to do this in batches). Cook the pork, stirring frequently, until it is browned and crispy all over. This should take 5-10 minutes, depending on how much pork you are doing at once.
3. Spread the bottom half of each toasted bun with a few spoonfuls of refried beans. Top this with a spoonful of guacamole, spread out evenly. Spoon some of the browned pork on top of the guacamole, then add pico de gallo to top off the sandwich. Put the top half of the bun on the torta and serve immediately.