To prepare a southwestern pulled brisket sandwiches recipe, you'll first need to prepare the pulled beef. Cut the beef into 1-inch (2.54-centimeter) cubes. Place the cubed beef in the crock-pot and cook over medium-high heat, stirring occasionally, until the meat is no longer pink and the juices run clear. Remove from the heat and set aside to rest for 10 to 15 minutes. Meanwhile, combine the barbecue sauce, ketchup, chili powder, cumin, and paprika. Toss the ingredients until evenly coated. Spread the mixture evenly on two slices of toasted white bread.