Add tofu, miso, ketchup, liquid smoke, tahini to a blender or use an immersion blender. Blend until smooth.
Whisk together the remaining dry ingredients in a large bowl.
Mix the liquid mixture with the dry mix using a heavy spoon or a stand mixer. Mix until no dry spots are visible. There is no need to knead.
Bring 8-12 cups of water to a boil in a 8 quart pot. While the water is coming to a boil start shaping the pepperoni.
Divide the pepperoni mixture into 3 equal pieces. Roll the pieces out to about 2" in diameter, length doesn't matter. Place the rolled seitan on a sheet of aluminum foil that is roughly 2' in length. Roll it tight and twist the ends to create a firm seal.
Place the wrapped seitan in the boiling water, turn heat to half for a simmer, and cook in the covered pot for 1 hour. Remove the cooked seitan and place on a wire rack to cool while still wrapped in foil. Allow to cool completely before freezing or refrigerating. Keep the cooked seitain pepperoni in the foil for freezing or refrigeration.
When ready to use, slice thin, about 1/8" thick, using a sharp knife and place on your pizza! See notes for an optional step. A mandolin cutter doesn't really work. Trust me, I've tried.