On a preheated skillet or comal, set over medium heat, toast the guajillos for about a minute per side, until fragrant and toasted. Transfer the chiles to a medium saucepan, along with the tomatoes and garlic, and cover with water and bring to a boil. Reduce to a medium simmer and cook for 10 minutes, until the chiles have rehydrated and the tomatoes have softened and cooked through.

Use a slotted spoon to transfer the guajillos, tomatoes, and garlic to a blender, add the onion and 1 teaspoon salt, and puree until completely smooth.

Heat 1 tablespoon of oil in a medium saucepan. Once hot, pour in the tomato sauce and cook partially covered with a lid for about 5 to 6 minutes, until thickened and seasoned.

Heat the remaining 2 tablespoons of oil in a large non-stick skillet over medium heat. Once hot, add the potato and nopal sticks, sprinkle with the remaining ½ teaspoon salt and black pepper. Cook, stirring occasionally, about 15 minutes until gently browned on the outside and softened inside – the liquid of the nopales will have come out and dried up, and the potatoes will have started to brown all over. Add the tomato sauce, toss well, and cook for 6 to 7 minutes more, until the sauce has thickened, absorbed, and mostly dried.

In a small skillet, cook the eggs sunny side up, one at a time, to desired doneness.

On a preheated comal, set over medium heat, heat the tortillas on both sides for about a minute until completely heated through.

Assemble the tacos by adding a big scoop of the nopalito and potato mix in the center of a tortilla, top with an egg, and sprinkle queso fresco on top. Continue with the rest of the tortillas!