Combine the oregano, salt, pepper, and cumin in a small bowl, rub over the pork.
Put the meat into a large slow cooker with the fatty side up.
Add the remaining ingredients, except the oil, to the slow cooker.
Cook for 9 to 10 hours on low.
When the meat is tender and can be shredded with a fork, it's ready.
Remove the meat from the slow cooker and reserve the cooking juices.
Shred the pork with two forks. Put the meat aside while you make the sauce. Any extra meat that you are not using for the meal can be stored at this stage.
Place the cooking juices in a saucepan over medium heat and simmer.
Stir occasionally until it had reduced to a thin sauce consistency.
To serve;
Add the oil to a non-stick frying pan over high heat.
Add enough pulled pork to cover the base of the pan. Cook without turning the meat until the bottom is crispy, repeat with the rest of the meat.
Remove the pork from the pan and serve dressed with some of the sauce.