Remove the stems and seeds from the dried ancho and guajillo chilies and pour boiling water over them in a bowl. Cover the bowl with a plate and allow the chilies to rehydrate for 15 minutes.
Add the chilies and all of their soaking water to a blender along with the the pinto beans, tomato paste, liquid smoke, and miso paste. Blend for about 60 seconds until smooth.
Add the vital wheat gluten, mushroom powder, and nutritional yeast to a bowl and put in the contents of the blender. Mix by hand for 1–2 minutes until a stringy elastic dough forms.
Divide the dough into 3 equal portions and firmly press each into a 1-inch–thick patty.
Place the patties in a steamer basket set over simmering water, cover, and steam for 40-45 minutes until firm to the touch.
Lightly brush the stewed seitan patties with olive oil, and cook them for 3-4 minutes on each side in a hot skillet over high heat until browned on the outside.
Remove from the pan and transfer the patties to a plate in your freezer for 20 minutes to cool completely. Once cooled, slice into 1 cm. thick strips.
To prepare the marinade, combine the chipotle peppers in adobo, onion, tomato paste, orange juice, lime juice, garlic, cilantro, brown sugar, and salt in a blender. Blend for 60 seconds on high speed until smooth.
Transfer the sliced seitan to a shallow container or resealable bag and pour the marinade over it. Stir to coat evenly and refrigerate for at least 2 hours, or up to 24 hours.
Warm the olive oil in a wide sauté pan over medium-high heat. After 90 seconds, when the oil is hot, add the marinated seitan and onions to the pan and cook for 6-7 minutes, stirring and flipping the pieces around occasionally, until the onions have softened, and the the seitan has browned and become slightly crisp on some of the edges.
To serve vegan carne asada tacos, warm the taco shells for about 30 seconds on each side in a pan over high heat, or more preferably for a few seconds on each side directly over an open flame.
Fill each taco shell with a portion of the seitan carne asada.
Top with salsa fresca, vegan cotija, sliced jalapeño, and fresh cilantro leaves.