In a small bowl, toss the grated carrots with the granulated sugar and unseasoned rice vinegar. Let stand for at least 30 minutes and preferably one hour at room temperature. Stir often.
In another small bowl, whisk together the mayonnaise and sriracha hot sauce. Chill until ready to use.
In a large bowl, combine the pork, garlic, green onions, jalapeño, lemongrass, fish sauce, sugar, salt and cornstarch. Shape the mixture into 16 golf-ball size meatballs and set aside.
In a large skillet, heat the sesame oil over medium heat until hot. Add the meatballs and cook for about about 12 minutes. Turn them often so they brown equally on all sides. Remove the meatballs from the skillet and set aside.
Cut the baguette pieces in half and pull out excess bread from the bottom half of the baguette to create a shell for the meatballs. Fill each shell with four meatballs and top with 1/2 cup of the carrot slaw. Sprinkle with cilantro leaves. Spread sriracha mayonnaise on the top halves of the bread and place on top of the meatballs. Serve.