To make Pickled Onions: Rinse and drain the onions under cold water. Combine them with all the other ingredients in a bowl and set aside for 10~15 minutes.
To make Salsa Roja/ Red Salsa: In a small pan, toast the chile de arbol until the color darkens. Set aside.
In a sauce pan, place tomatoes, guajillos chiles and onion. Pour water until the the ingredients are submerged. Cover and cook till the tomatoes are tender, about 8~10 minutes. Cool slightly. When cool enough to handle, remove the skins of the tomatoes and reserve 1½cups of the cooking liquid and drain the rest.
Blend the tomato mixture along with the toasted chiles, garlic, salt and 1 cup of the reserved water until smooth. Add more water if needed.
To make Chilaquiles: Heat enough oil in a skillet. Once the oil starts to ripple, add the tortillas and fry them until evenly golden on all sides. Remove onto paper towel lined plate. Fry the tortillas in batches, do not overcrowd the pan.
Remove all but 2tbsp oil from the pan. Once the oil is hot, gently pour in the red salsa and cook for 1~2 minutes, stir until bubbly.
Cook the eggs to desired consistency and keep warm.
Add the fried tortillas, mix well and cook for 1~2 minutes. Remove onto the serving plate and serve right away with the egg on top. Garnish with crema, queso fresco, onions, refried beans and avocado slices. Enjoy!!