Despite the influence that geography has on salsa, there are no rules, no one dish that you serve a type of salsa with. And depending on technique, one set of ingredients can produce very different results. Roasting, for instance, renders tomatillos jammy, and mellows seasonings like chiles and garlic. If you prefer chunky salsa, pound garlic, chile, and salt to a paste in a molcajete, then mash in roasted tomatillos. For a smooth salsa, puree those ingredients in the blender. For a concentrated condiment, season the puree to the hilt with salt, lime juice, and chile, to make an intense sauce that matches emphatically flavored foods such as bluefish or lamb. To make a cooking liquid, dilute the sauce with water and simmer it to meld the flavors.