Remove the pork tenderloin from the package, and place it on a cutting board.
In a small bowl combine the salt, smoked paprika, garlic powder, and onion powder. Mix to combine.
Rub the spice mixture all over the tenderloin then place it in the bottom of the slow cooker.
Add the water or chicken stock to the bottom of the slow cooker (don't pour it over the pork, though, so that you don't wash off your spice rub).
Add the lid and cook on high for 4-5 hours, or until the tenderloin is easy to shred with a fork.
Remove the pork from the crock pot, and shred with 2 forks. Return it to the slow cooker, and mix it with any liquid that might have remained in the bottom of the slow cooker.
Add the BBQ sauce, and stir to combine. Adjust salt and BBQ amounts to your liking serve warm.
Notes
This recipe is really easy to scale up. If you are feeding a crowd, you can put up to 3 or 4 tenderloins in the slow cooker at a time. The cooking time will increase as the pounds of pork increases.
To cook the pork tenderloin more quickly, cut the tenderloin into 3 or 4 chunks. When it's cut up, it could take as few as 3 hours to cook until tender.
I like adding the BBQ sauce to the pork after cooking for a few reasons. It doesn't overcook the sauce or "burn" it. Not everyone likes BBQ in my house, so I'll pull some of the meat out before adding the sauce for those who don't like it.
Please don't substitute regular paprika for the smoked. Smoked paprika is a must-have for this recipe's amazing flavor!