In a medium pot, add the chiles de arbol and enough water to completely cover them. Bring to a boil over high heat.
Remove the pot from the heat, cover, and let the chiles soak for 10 minutes to soften.
Using a slotted spoon, transfer the softened chiles to a blender. Add ¾ cup of fresh water, the tomatoes, garlic, and salt. Blend until completely smooth.
Taste and add more salt as needed.
