Preheat oven to 350°. Bake baguette on an ungreased baking sheet 10 minutes or until warm.
Meanwhile, stir together mayonnaise and sriracha in a small bowl. Stir together carrots and fish sauce in a separate bowl.
Split baguette horizontally. Cut each half into 3 (6-inch-long) pieces. Spread cut sides of bread with mayonnaise mixture. Layer bottom halves with Slow-cooker Mustard Barbecued Pork, Pickled Peppers and Onions, serrano pepper slices, carrot mixture, and cilantro to taste. Top with remaining bread slices. Serve immediately.
* 1/2 small jalapeño pepper may be substituted.
To make appetizer servings, cut baguette into 6 (3-inch-long) pieces instead of 3 (6-inch-long) pieces.