To prepare the Broccoli Slaw: In a screw-top jar combine vinegar, honey, salt, black pepper, and, if desired, bottled hot pepper sauce. Cover and shake well. In a medium bowl combine broccoli, green onion, and parsley. Pour vinegar mixture over vegetable mixture; toss to coat. Cover and chill for 2 to 24 hours before serving.
To prepare the Pork Tenderloin Sandwiches: Cut pork crosswise into four pieces. Place one pork piece between two pieces of clear plastic wrap. Pound lightly with the flat side of a meat mallet, working from center to edges until ¼ inch thick. Remove plastic wrap. Repeat with remaining pork pieces.
In a shallow dish, combine flour, salt, onion powder, cayenne pepper, and black pepper. Dip meat into the flour mixture, turning to coat. In a very large skillet, heat oil over medium heat. Add pork; cook for 8 to 10 minutes or until no pink remains and juices run clear, turning once. (If all the pork slices won't fit in the skillet, cook in two batches, adding additional oil if necessary.)
To serve, place pork pieces in buns. Serve with Broccoli Slaw. If desired, serve with ketchup, mustard, and/or pickles.