Combine 1/4 cup salsa and conrstarch in small bowl; stir until smooth. Pour mixture into slow cooker. Top with pork roast. Pour remaining 3/4 cup salsa over roast. Cover, cook on LOW for 6 to 8 hours.
Transfer roast to cutting board. Trim and discard fat from pork. Pull pork into coarse shreds using 2 forks.
Divide shredded meat evenly among tortillas. Spoon about 2 tablespoons salsa mixture on top of meat in each tortilla. Top evenly with broccoli slaw (and cheese, if desired.) Fold bottom edge of tortilla over filling; fold in sides. Roll up completely to enclose filling. Serve remaining salse mixture from pot as dipping sauce.