Make 6 cuts in the pork, 1 inch apart, cutting most of the way through the meat. Rub the pork all over with the salt. Rub the pork with the garlic and then with the Aleppo pepper, covering the meat completely. Wrap the pork in plastic and refrigerate overnight.
Preheat the oven to 325°. Set the pork in a baking dish just large enough to hold it and add 1/4 cup of water. Cover the pork with parchment paper and then cover tightly with foil. Bake for about 2 1/2 hours, until the meat is very tender.
Pour all but 1/4 cup of the roasting juices into a bowl and reserve. Drizzle the pork with the vinegar, cover with foil and bake for 10 minutes. Remove the pork from the oven and let it rest, covered, for 10 minutes.
In a large bowl, stir the olive oil with the lemon juice and season with salt and black pepper. Add the fennel and arugula and toss.
Discard any fat and gristle from the pork. Shred the meat into large pieces and toss with the pan juices and reserved juices. Pile the meat on the rolls, top with the fennel salad and serve.