This is a condiment salsa, for carne asada, tacos or eggs. You can toast everything on a comal (a flat pan used for heating tortillas and toasting chiles and vegetables. You can find one at a Latino grocery), broil, grill, or boil your tomatillos. Throwing them on the grill or toasting them on a comal gives them more flavor!
Peel wash and dry tomatillos. Break off stems of the chiles. If you want less spicy salsa, discard some or as many of the seeds as you can. Heat comal or a heavy skillet on medium low heat. Place the chiles on the comal and toast and turn them with tongs until they turn a light tobacco brown color. DO NOT BURN THEM. They get bitter. If you burn them, trust me, start over. When toasted, put them in the boiling water to sit for about 10 minutes. While they're soaking, toast, roast, grill or boil your tomatillos. If you're boiling, you can do it along side the chiles. They are done when they're soft and a golden color, rather than green.
In a blender jar, place soaked chiles, garlic salt and half of the water. Blend on high until the ingredients become a smooth red paste (about 2 minutes). Add cooked tomatillos and the rest of the water and blend until smooth. You may need more water. You can add spices such as oregano or cumin while blending, too. I'm a purist, though! Enjoy!