In a large non-stick skillet, brown ground beef and onion over medium heat until beef is no longer pink breaking beef into crumbles as it cooks. Drain and season with salt and pepper. Stir in slaw mix and 1/4 cup hoisin sauce; heat through.
Spread 1/4 of beef mixture (about 1 cup) evenly over each tortilla, leaving 1-1/2-inch border on all sides. Fold right and left edges of tortilla over filling; fold bottom edge up over filling, then rollup jelly-roll fashion. Place seam-side down on plates; cut in half, if desired. Serve with additional hoisin sauce, if desired.