In a bowl combine the spices for the BBQ rub. Toss this with the pork cubes, turning to coat.
Heat the oil on saute until shimmering. Add the seasoned pork cubes. Brown quickly, until all sides have a nice crust, turning as needed.
In a small cup combine the water, tomato sauce, and vinegar. Add this to the pot.
Secure the cover and lock the pressure valve. Set the machine for 45 minutes on manual.
One the timer rings, wait ten minutes before releasing the pressure. The meat should be fall-apart tender. Shred the meat and moisten with some juices if needed. Adjust the seasonings to your taste.
To serve: Assemble the sandwiches by placing a generous amount of shredded pork on hamburger buns. Top with BBQ sauce and dill pickles. Serve immediately.
Promptly refrigerate leftovers and use within 4 days. For longer storage, cool the meat completely, package for freezing, and store in the freezer, for up to 2 months.
Notes
Nutritional values are approximate and based on 1 sandwich.