Remove the husks from the tomatillos and rinse the tomatillos under running water.
Place the chiles in a pan with just enough water cover them, bring to a boil and then turn off the heat. Allow them to soak for 15 minutes.
Place the tomatillos in a pan with just enough water to cover, bring to a boil then reduce the heat to low and simmer for 15 minutes. Blend the chiles and tomatillos with a little of the tomatillo cooking water, about ½ cup for 45 seconds.
Put the blended salsa and 1 tsp. of salt into a pan over low heat and simmer for 15 minutes.
Adjust the salt to taste.
You can serve the salsa immediately but it tastes even better if you can allow it to rest for 1 hour to allow the flavors to meld.
If you want an extra tangy salsa add 1 tsp. of apple cider vinegar when you are simmering.