|Dried Ancho chiles, untoasted on left, toasted & chopped on right|
Here are two simple ways to dry-roast or toast dried peppers. If you're toasting only 2 or 3 chiles, the stove-top method works very well -- just make sure to use a cast-iron skillet or anything other than a nonstick-coated pan. For toasting more than 2 or 3 chilies, I recommend the oven method. Either way, it only takes a few minutes and is well worth it. Be sure not to over-toast or burn them, because that can bring out harsh or bitter flavors. Toast only until the peppers are hot to the touch, with a slight change in color and pleasantly fragrant -- if you start smelling acrid odors, they've gone too long.
Stove method: Heat an ungreased heavy-bottomed skillet or griddle over medium heat until hot. Add dried chilies in a single layer and toast for 1 to 2 minutes per side, pressing down with a spatula for more even toasting (the peppers will soften as they heat up). Toast until their color begins to change and they become aromatic. Remove from heat and let cool just enough to handle, then use kitchen scissors to snip off the top, cut lengthwise and remove the seeds and ribs.
Oven method: Preheat oven to 350°F. Place dried chiles on an ungreased baking sheet in a single layer and dry-roast (toast) until fragrant and hot to the touch, about 5 minutes -- they'll become pliable and you should see a slight change in color, maybe a few brownish spots, but they should not smell acrid or look burnt. Remove from oven and let cool just enough to handle, then use kitchen scissors to snip off the top, cut lengthwise and remove the seeds and ribs.
PS: If you've always wanted to try dried chili peppers but aren't sure how to start, read my post on how to use dried peppers.