Remove the stems and seeds from the guajillo chiles, then soak them in warm water.

Blend the soaked chiles with onion, garlic, cumin, salt, and the water.

Strain the sauce, then dip the tortillas in it.

Heat a little oil in a skillet and cook the sauce-coated tortilla.

Fill the tortilla with the mashed potatoes, roll it up, and serve with sour cream and cheese as desired.