2 French rolls (the crustier the better, but no sourdough!)
3 tablespoons vegan mayonnaise (I use Veganaise)
1 teaspoon sesame oil
1/2 teaspoon rice vinegar
2 tablespoons sweet chili sauce
2 seitan cutlets
1/2 cucumber, sliced into strips
1 jalapeno, sliced into thin strips
10 pickled daikon strips, divided
10 pickled carrot strips, divided
1 bunch cilantro
1. Put the bread in an oven set at 350 degrees F for a few minutes until warm and the outside is crispy.
2. Remove rolls, split open and tear out some of the soft bread in the middle to make room for all the delicious fillings!
3. Mix together vegan mayo, sesame oil, rice vinegar and chili sauce. Spread onto rolls, using as much as you like.
4. Place a few pieces seitan on each roll, add cucumber and jalapeno strips, 5 spears daikon and carrots on each, and a few sprigs cilantro.
Enjoy! I think they taste close to the real thing, tweak the recipe as you see fit! This recipe takes some preparation unless you have seitan and pickled daikon/carrots already on hand. I couldn't find pickled daikon/carrots in the store so I made them a few days before with this recipe: http://simplyrecipes.com/recipes/vietnamese_daikon_and_carrot_pickles/  as well as making the seitan the day before using this recipe: http://www.theppk.com/2009/11/homemade-seitan/ 
Source of recipe: I made this recipe up because I was craving a banh mi but it's pretty difficult to find vegan ones. so here it goes.