Place guajillo and chipotle chiles in a large heatproof bowl and pour in boiling water to cover. Let chiles soak until softened, 40–45 minutes; drain.

Grind nigella seeds and coriander seeds in a spice mill or with a mortar and pestle. Transfer to a food processor and add garlic, cumin, salt, and Aleppo pepper and pulse until garlic is very finely chopped. Add chiles and pulse until they are chopped. Add oil and vinegar and pulse just until incorporated (mixture should have the tex