In a small bowl, combine olive oil, tomato paste, brown sugar substitute, cumin, oregano, salt, chili powder, garlic powder, onion powder, paprika, pepper, and chipotle powder. Stir to mix.
Place the pork shoulder in the bowl of the slow cooker. Rub the spice mixture all over the outside of the pork shoulder.
Add the lime juice to the slow cooker.
Top the pork shoulder with chopped onion and jalapenos.
Cook on low for 8 to 10 hours or high for 5 to 6 hours.
When pork is cooked through, remove from slow cooker and shred with a fork.
Preheat the oven to 350 degrees. Place the shredded pork on a baking sheet and top with ½ cup of juices remaining in slow cooker.
Bake for 15 minutes to crisp the edges of the meat.
Serve in low-carb tortillas, over cauliflower rice, or enjoy one of the many serving ideas listed in the blog post above.