Roast tomatillos under broiler set to high for 5 minutes, turn over and roast for another 5 minutes. In a blender or food processor, pureetomatillos. Allow to cool completely.
In a small bowl, mash the chopped avocado with the back of a fork until it’s smooth but still a little chunky. Stir in tomatillo puree, lime juice, 1/4 tsp salt, pepper, garlic powder, and cayenne. Set aside in the refrigerator until ready to serve.
In a small skillet, add canola oil until about 1 inch deep. Heat oil over medium-high heat. Once the oil is hot and shimmering, fry corn tortillas one at a time, until golden brown, approximately 1-2 minutes per side. Remove to a paper-towel lined plate to drain and sprinkle with salt. Repeat with the remaining tortillas. Set aside.
In a large skillet, add enough canola oil to just cover the bottom of the pan. Heat the oil over medium-low heat. Add each egg to its own corner of the pan and cook sunny-side up. I like to use the technique of spooning the hot oil over the whites until they’re cooked, then spooning the oil over the yolk a couple times. Remove eggs from the pan with a slotted spatula to a clean plate.
To assemble the tostadas, spread a thick layer of guacamole on each crispy tortilla. Add a layer of salsa, top with a sunny-side up egg and serve with extra salsa and hot sauce, if desired.