Prepare the marinade by combining all the ingredients to a bowl.
Cut the natural seitan into bites/pieces and add it to the marinade (pieces might stick together, it doesn't really matter as we are going to eventually chop the seitan again).
Heat the vegetable oil in a pan, add the seitan pieces drained from the marinade (do not throw the liquid away!) and sauté until caramelized on both sides. Set aside to cool.
In the same pan pour the rest of the marinade and reduce on medium heat for 4-5 minutes. Set aside.
Julienne cut the carrot, the spring onions and the cucumber (de-seeded) and finely slice the lettuce.
Finely cut or shred the seitan "duck".
Assemble the wraps by adding some salad, carrots, cucumber, spring onions and seitan duck to a tortilla, drizzle some reduced hoisin sauce on top and wrap tightly.
Serve the homemade hoisin duck wraps with the remaining reduced sauce.