Warm a dry comal or skillet over medium heat; toast the chiles quickly, taking care not to let them burn. Toast the tomato until the skin is blackened and the inside is soft, 15 to 20 minutes.
In a bowl, combine the toasted chiles, vinegar, and lime juice; let the chiles hydrate for 15 minutes.
In a blender, process the chiles, tomato, cumin, and garlic until smooth. Blend well, scraping down the paste as needed. Use a wooden spoon to push the mixture through a fine-mesh sieve into a small bowl, discarding the skins and seeds. Taste and add salt, as desired.