Preheat oven to 350 degrees.
Place corn tortillas onto baking sheet. Spray both sides with olive oil.
Bake corn tortillas for 10 minutes, flipping halfway through.
Remove from oven and set aside.
Spray frying pan with olive oil spray and add in spinach. Cook spinach over medium heat for 2-4 minutes until begins to look "wilted".
Sprinkle spinach with salt. Remove from pan and set aside.
Into the pan, add ham, cook over medium heat for 2-4 minutes until warmed through. Again, remove from pan and set aside.
Heat refried black beans for 1-1 1/2 minutes until warmed.
Finally, cook your eggs (cook 1 egg at a time).
Crack an egg into a small bowl. Into the frying pan heat up 1/2 tbsp of butter over low-medium heat.
When butter is melted, carefully pour egg into the pan. Sprinkle on 1/3 portion of black pepper onto egg then allow to fry for 2 minute until whites begin to show their color.
Cover pan with lid and cook egg for 2 more minutes until all whites are cooked. Remove egg and complete steps until all are cooked.
Assemble your breakfast tostadas. Begin by adding a scoop of black beans to your corn tortilla, spread it out out across the tortilla.
Top the black beans with sauteed spinach and then ham. Finally top tostada with fried egg.
Optional: Add freshly sliced avocado or pico de gallo to tostada. Serve immediately and enjoy!