Combine the 1 cup each of kosher salt, pepper and paprika; coat pork butt evenly with mixture. Prepare smoker with apple and hickory chips; smoke pork butt over low fire for about 8 hours. Let cool slightly; break meat apart with forks.

Saute onions in oil in heavy saucepan until translucent; stir in the tablespoon of paprika, chili powder, red pepper, cumin and cayenne, cook until fragrant, 1 minutes. Add tomatoes, vinegar, ketchup, orange juice, brown sugar, mustard, and tablespoon of salt and black pepper. Cook, stirring occasionally, until mixture is thick and coats back of spoon. Puree sauce and let cool. Sauce can be made 2-3 days in advance and refrigerated.

Combine pork and sauce in large saucepan; heat through, stirring over medium-low heat. Pile sauced pork on buns.