Toast chiles in a skillet over medium heat, turning often, until they start to brown lightly in spots, about 3 minutes. Transfer to a plate.

Place chiles, tomatillos, garlic, and 2½ cups water in a medium saucepan and season with salt. Cover, bring to a simmer, and cook until tomatillos turn olive green and burst, 5–8 minutes. Remove from heat and let sit (covered) 5 minutes.

Using a slotted spoon, transfer chiles, tomatillos, and garlic to a blender or food processor; add ½ cup cooking liquid from saucepan and purée until smooth. Add lime juice and season with salt to taste. Let cool completely before serving.