Position racks in the upper and lower thirds of the oven and preheat to 450 degrees . Place all of the pork in a large roasting pan. Sprinkle with the garlic, lemon zest, 1 tbsp. salt and 1 1/2 tsp. pepper. Toss well, massaging the garlic and zest into the meat. Transfer half of the pork to a large rimmed baking sheet and place both the roasting pan and the baking sheet in the oven. Roast until the meat is browned on top, about 30 minutes. Turn the pork chunks over and roast to brown the other side, 15 minutes. Remove both pans from the oven and lower the oven temperature to 325 degrees .
Using tongs, transfer the pork from the baking sheet to the pork in the roasting pan. Pour the pan juices from the baking sheet over the pork and add the wine (if using). Tightly cover the pan with foil. Continue roasting the pork until nicely tender, about 1 hour 45 minutes. Meanwhile, wash and dry the baking sheet and set aside.
Let the pork cool for at least 15 minutes, then, using 2 forks, shred it a few pieces at a time. As you work, transfer the shredded pork to the clean baking sheet and let cool completely. Pour the juices into a bowl to cool. Skim and discard the fat.