If your skewers are bambo, place them in a bowl or baking dish and cover with water. Let them soak while you prepare the seitan.
Preheat your oven to 350° and oil a medium-sized baking or casserole dish.
Mix together the spice rub and set aside.
Mix together the seitan dry ingredients in a large bowl then whisk together the seitan wet ingredients. Pour about half of the liquid into the dry mix and mix together. Add the remaining wet ingredients a little at a time to the dry mixture, mixing and kneading as you go. The dough should be firm and shouldn’t tear apart easily. Kneed the dough for several minutes. If your dough seems to soft, you can add a little more vital wheat gluten. If it's too dry, you can add little more vegetable stock.
Flatten and stretch the dough until it is about an inch thick. Place the seitan in the baking dish, and gently rub half of the spice mixture over the surface. Flip the seitan and rub the rest of the spices onto the other side.
Place the dish in the oven and bake for 20 minutes Remove the dish from the oven and carefully flip the seitan over. Bake for another 20 minutes, and remove from the oven. The seitan should be firm and meaty. If it is too soft, you can place it back in the oven and bake for a few more minutes, until it reaches the desired consistency.
Let the seitan cool for a few minutes and then cut it into cubes, about 1 1/2-inches in size. Thread a few pieces onto the bamboo skewers. Continue until you’ve used all of our seitan and skewers.
Grill the skewers using an outdoor grill, an indoor electric grill, or a grill pan on the stovetop. Grill for 3 to 5 minutes on each side.
Remove the skewers from the heat, place on a plate and drizzle with the chimichurri and aioli. Serve the rest of the two sauces on the side for dipping.