Method
Roast the tomatoes in a dry skillet until softened and lightly charred.
Toast the dried chiles briefly in the skillet until fragrant.
Soak the toasted chiles in hot water until softened.
Blend the tomatoes, softened chiles, garlic, onion, and salt until combined.
Taste and adjust the seasoning before serving.
Notes
Use fewer dried chiles for less heat; refrigerate leftovers in a covered container for up to 4 days.