The night before you plan to roast the pork, score the skin with a sharp paring knife in a cross-hatch pattern. Then, season the whole roast liberally with salt and Chili Con Carne seasoning.
Place the roast in the fridge to marinate overnight (12-24 hours).
When you're ready to cook the roast, preheat your oven to 275° F and take the roast out of the fridge.
Cover a baking tray with heavy-duty aluminum foil and place the chopped veggies on top to make a rack for the roast to lay on top of. Lay the roast on top of the layer of veggies and let everything sit on the counter for over an hour to bring the pork up to room temperature.
When the roast has come up to room temperature, place the roast in the oven and let it slowly roast for 8-10 hours or until the meat is fork-tender.
Discard the vegetables and transfer the roast to a platter to rest for 30 minutes.
Peel off the skin and fat and shred the meat with your hands.