Fill 6-quart saucepot with 1 inch water and add steamer insert. Cover; heat to boiling on high. Reduce heat to medium. In small bowl, combine chili powder, smoked paprika, dry mustard, 1/4 teaspoon salt, and 1/4 teaspoon freshly ground black pepper. Rub spices all over pork. Place pork in steamer; cover and steam 18 to 20 minutes or until pork is 145 degrees F in center, turning over once.
Meanwhile, in medium bowl, toss cabbage mix with 2 tablespoons vinegar, chives, 1 tablespoon mustard, and 1/8 teaspoon salt; set aside.
Transfer pork to plate. Discard water in pot; remove steamer. When cool enough to handle, shred pork into bite-size pieces.
Return pork to saucepot. Stir in barbecue sauce, 1 tablespoon water, and remaining 2 teaspoons mustard and 1 teaspoon vinegar. Cook on medium until hot, stirring frequently. Divide pork and slaw among buns.
Serve each sandwich with: corn on the cob (60 calories) with smoky butter made from 2 teaspoons light butter (35 calories) and a pinch of smoked paprika.
Nutritional Information (per serving):Calories 300; Total Fat 6g; Saturated Fat 1.5g; Cholesterol 60mg; Sodium 690mg; Total Carbohydrate 33g; Dietary Fiber 5g; Protein 27g