Make the chipotle chile sauce: Put the ancho chile in a small bowl and pour the boiling water over. Let sit until the chile is deep red and soft, about 20 minutes.
Meanwhile make the pickled red onions: In a small bowl, combine the sliced red onions and lime juice. Season with kosher salt and set aside to macerate.
In large sauté pan over high heat, warm the canola oil for the sauce and add the onions. Season with the kosher salt and cook, stirring often, until the edges turn dark brown, about 5 minutes. Add the garlic and cook until golden brown, another minute, and remove from the heat.
When the ancho chile is soft, destem it and remove its seeds, reserving the water. Add the chile and ½ cup of the ancho water to a blender base, along with the onion-garlic mixture, tomato sauce, chipotle chile and its chile adobo sauce. Purée on medium-high speed until smooth. Return to the large sauté pan and bring to a low boil over medium-high heat. Reduce the heat to low and keep warm. Makes about 3 cups.
Make the chorizo chilaquiles: In small sauté pan over medium-high heat, warm the canola oil. Add the chorizo and cook, breaking the meat apart and stirring with a wooden spoon until browned, 3 to 4 minutes. Push the meat to the side of the pan and add the egg, frying it in the chorizo fat, until the whites are completely cooked and the yolk is barely set, about 3 minutes.
Return the chipotle chile sauce to a simmer over medium-high heat. Taste and adjust the seasoning with salt as needed. If the sauce has reduced too much, add a few tablespoons of water. Add the tortilla chips and toss with a large slotted spoon to coat. Scoop out the chips with the spoon, letting excess sauce drip back into the pan, and transfer to a large serving bowl. Sprinkle with the chorizo, queso fresco and the pickled red onions. Top with the fried egg and cilantro, and serve with the sour cream, avocado slices and lime wedges.