Heat a grill to high or preheat a broiler. Place the tomatillos, onion, chiles, and garlic cloves directly onto the grill grates (or on a foil-lined baking pan about 4-inches from the broiler unit) and grill/broil, turning occasionally, until well-charred, usually about 6 to 10 minutes. 

As the vegetables are finished charring, transfer them to a blender (garlic cloves should slip right out of their skins).  Add the roughly chopped cilantro and blend to roughly puree – you don’t want the salsa to be completely smooth. 

Season to taste with salt and add the finely chopped cilantro.