On a large plate, combine the salt, pepper, cumin, chili powder, and cinnamon. Rub the spice mixture evenly over the pork tenderloins.
Heat the oil over medium high heat in a large skillet. Add the pork and brown on all sides, 4-5 minutes per side. Remove the heat from the pan. Transfer the pork to the slow cooker.
Add ½ cup of water to the hot, now-empty pan and scrape any browned bits to deglaze. Pour the liquid into the slow-cooker. Add the brown sugar, garlic, and hot sauce. Combine and cook on low for 4-6 hours. (Now is a good time to make the pickled onions so they can sit!)
Shred the meat before serving and mix with the sauce. Season it with more salt, hot sauce and sugar if needed. I almost always add a little more salt. Enjoy!