In a bowl, whisk together soy sauce, fish sauce, lime juice, honey, garlic, ginger, and black pepper. Add chicken and marinate for at least 30 minutes.
Meanwhile, in a small bowl, combine rice vinegar, sugar, salt, and water. Add the julienned carrots and daikon radish. Let sit for at least 15 minutes.
Heat a grill or skillet over medium heat. Cook the marinated chicken for 5-7 minutes per side, until fully cooked and slightly charred. Let rest before slicing.
Spread mayonnaise on both sides of the baguette. Layer with cucumber slices, grilled chicken, pickled vegetables, jalapeño, and cilantro.
Close the sandwich and serve immediately.
Notes
For extra crunch, lightly toast the baguette before assembling the sandwich.