Rub the pieces of pork shoulder all over with salt. Place in a ziplock bag and refrigerate for 1- to 3-days. (You can skip this step if you want. Just be sure to salt the pork before searing the meat in the next step.)
Heat the oil in a large Dutch oven. Cook the pieces of pork shoulder in a single layer until very well-browned, turning them as little as possible so they get nice and dark before flipping them around. If your cooking vessel is too small to cook them in a single-layer, cook them in two batches.
Once all the pork is browned, remove them from the pot, then pour in about a cup of water, scraping the bottom of the pan to release all the tasty brown bits.
Heat the oven to 350F degrees.
Add the pork back to the pan and add enough water so the pork pieces are 2/3rd’s submerged in liquid. Add the cinnamon stick and stir in the chile powders, bay leaves, cumin and garlic.
Braise in the oven uncovered for 3½ hours, turning the pork a few times during cooking, until much of the liquid is evaporated and the pork is falling apart. Remove the pan from the oven and lift the pork pieces out of the liquid and set them on a platter.
Once the pork pieces are cool enough to handle, shred them into bite-sized pieces, discarding any obvious big chunks of fat, as well as the bay leaves and cinnamon stick.
Return the pork pieces back to the roasting pan and cook in the oven, turning occasionally, until the liquid has evaporated and the pork is crispy and caramelized. It will depend on how much liquid the pork gave off, and how crackly you want them.
If making these into sliders, toss the pork with your favorite BBQ sauce and top with pickled red onions.