Prep all ingredients per the instructions above.
Cook the chicken: Heat a skillet over medium-high heat. Add a little oil to the skillet and saute the chicken until it's browned on all sides and fully cooked. Then set it aside.
Prepare the Banh Mi Sauce: In a small bowl, whisk together mayonnaise, sriracha sauce, soy sauce, rice vinegar, and sesame oil until well combined.
Assemble the Banh Mi Sandwiches: Slice the baguettes or sub rolls lengthwise, but not all the way through. Open the bread and spread the Banh Mi sauce generously on both sides. Layer the cooked chicken, pickled carrots and daikon, cucumber slices, fresh cilantro leaves, and jalapeño slices (if using) on the bottom half of the bread. Close the sandwich.
Serve the Banh Mi sandwiches with chips, pickle, and lemonade, with ice if desired.