Almost always, this simple procedure is the prelude to using dried chiles for my recipes. Very tiny chiles are toasted or blanched whole before cooking, and I have seen Oaxacan cooks fry larger chiles before soaking them, but the following method is the one I find best for chiles to be used in sauces.

Griddle-Drying. Unless otherwise directed in a recipe, remove and discard the tops and seeds of the chiles. I leave in the veins (the hottest part) but you can cut them away if you want to tone down the heat. Rinse the chiles under cold running water and shake off the excess moisture, but do not dry them. Heat a griddle or cast-iron skillet over medium-high heat until a drop of water sizzles on contact. A few at a time, place the chiles on the griddle and let them heat, turning occasionally with tongs, just until any clinging moisture is evaporated and the aroma is released. Allow between 30 to 45 seconds in all per chiles of most kinds- slightly less for guajillos (which are very thin-skinned). The chiles should just become dry, hot, and fragrant; do not allow them to start really roasting or they will have a terrible scorched flavor. Remove from the griddle as they are done. Most recipes will call for placing them in a deep bowl, covering generously with boiling water, and letting stand for about 15 – 20 minutes, then draining well.

See my video on youtube Working with Dried Chiles