In a large bowl combine the carrot, cucumber, daikon, scallions, vinegar, fish sauce, and salt and pepper. Stir to combine. Then (ideally) refrigerate for 1 to 2 hours to let the vegetables pickle slightly. Stir in the mint and cilantro.
In a small bowl combine the mayonnaise with the hot chili sauce, and the lime juice. Season with a bit of salt.
When you are ready to assemble and serve the sandwiches, halve the baguette lengthwise. Place ¼ of the pork on the bottom of the baguette, cutting the pork to fit the baguette. Layer on some of the slaw, then drape a pieces of prosciutto over the slaw. Top with ¼ of the arugula. Swipe the top of the baguette with the spicy mayo and place the bread on top.
The cilantro is, as it always is, optional, since there are lovers (me and Charlie) and haters (Gary and Jack) in every crowd. Play around with the herbs, too – chervil is great, so is basil.