In a medium-sized mixing bowl, toss together the vital wheat gluten and chickpea flour, and then add the water and mix until it forms a ball (I like to use a dough hook, but a regular spatula or mixing spoon will work fine too).
Remove the dough from the bowl and knead for 5 minutes. Form the dough into a nice ball and let it rest for 5 minutes.
After it has rested, form it into a log shape and wrap it in cheesecloth, securing the ends with baker's twine.
In a large pot, add the onion, garlic, lemongrass, ginger, peppercorns, and soy sauce. Place the seitan log in the middle of the pot and add add enough water to cover 3/4 of the seitan log. Salt the water enough so that it tastes like the saltiness of sea water.
Turn on the stove and bring the liquid to a boil, then quickly reduce to a simmer (you don't want to boil the seitan or it will become too chewy). Simmer for an hour, then remove from the heat.
After the seitan is cooked, let it cool and then you can remove it from the cheese cloth and either tear it into pieces or slice it into chunks or "steaks" to be cooked again in whatever sauce you plan to serve it in. The seitan can be pre-made up to 5 days in advance. To store it, just put the pieces, chunks, or steaks into an air-tight container and pour the cooking broth over it to keep it from drying out.