Mix the yeast, lukewarm water, and oil in a small bowl and let stand at room temperature for about 20 minutes, until frothy.
Sift the flour and xanthan gum into a large bowl and make a well in the center. Add the yeast liquid to the well slowly with the cilantro, crushed red pepper, if using, salt, and pepper. Mix well to form a sticky dough.
Invert onto a floured surface and knead well. Divide into 8–10 small balls.
Cut out an 8-inch circle of parchment paper and roll out each ball of dough under it, the thinner the better.
Place a nonstick skillet on medium heat. Add the tortillas to the skillet, one at a time, with the parchment paper underneath and cook for 2–3 minutes, until golden brown. Flip over, remove the paper, and cook the other side for 2–3 minutes, until golden brown. If the paper starts to scorch, cut a new circle.
Serve hot or cold with your favorite fillings. To store, stack each tortilla between parchment paper to prevent them from sticking and keep in an airtight container for up to one week or freeze for one to two months.
This recipe is excerpted with permission from <a href="http://www.amazon.com/gp/product/1445498278/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1445498278&linkCode=as2&tag=craftfocom-20">"Gluten Free Baking (Love Food)"</a> by Michael McCamley and published by Parragon Books.