
Combine salt, five-spice powder, garlic powder, paprika and black pepper in a bowl. Rub the spice mixture all over the pork shoulder/butts.
Transfer the pork to the slow cooker, add the water. Cook on low for about 8 hours (or 6 hours on high) or to desired tenderness.
Julienne carrots and cucumber (or daikon radish). If using cucumber, remove all seeds before you julienne them. In a jar or bowl, combine rice vinegar, water, sugar and salt, and then add the veggies. Cover, refrigerate to pickle for 2-3 hours or overnight.
In a bowl, mix together mayonnaise, sriracha, lime juice and honey to make the sauce. Add salt and pepper to taste.
Shred the pork. Slice the banh mi (or baguette) open lengthwise, fill with pulled pork, pickled veggies and cilantro, then drizzle with plenty of sauce. Serve immediately.