If brining, put 1/2 cup of salt into a container and cover with enough water. Sit in the fridge for 18-24 hours.
Preheat oven to 250 degrees F. Remove shoulder from brine and pat dry. Cover the shoulder in mustard. In a bowl combine the oregano, paprika, garlic powder, black pepper, salt and rub all over the meat.
Place meat on a rack over a roasting tray with 1/2 Cup of water and place in the oven to cook for 8-10 hours. If you have a thermometer you want the internal temperature to be 190 degrees F.
For The Beans:
With 1 hour remaining on the pork cooking process remove the shoulder from the oven and transfer to a plate, cover with foil. Transfer all but 2 tbsp of the pork juices to a jar or bowl.
Transfer roasting pan to stove top and on medium-high heat cook the leek and onions and garlic for 5-7 minutes, before adding in the apples and beans, stir for a minute then pour in the stock and the rest of the ingredients. Bring to a boil and place roasting tray in the bottom of the oven.
Place the shoulder on a rack on top of the tray dripping its awesomeness into the pan. Cook for 30-45 minutes or until beans is super gelatinous and mushy.
For The Slaw:
Combine all the ingredients and set aside for 30 minutes.
Serve Pork to the table on top of the beans with the slaw on the side… you will need 2 forks for the pulling :).