Preheat your oven to 375 degrees and line a large baking sheet with parchment paper. Then place your tortillas on the sheet and spray both sides with avocado oil (or rub both sides with olive oil.) Bake the tortillas for 12-16 minutes or until crispy. Set them aside while your prepare the rest of your tostadas.
Bring a large pot of water to a boil on the stove and remove the husks from your corn. Once boiling, add your corn cobs to the water and boil for 1-2 minutes. (The kernels should be plump and turn bright yellow.) Then remove the corn and discard the water. Allow the corn to cool completely before cutting off the kernels. Then add the corn kernels and the rest of your salsa ingredients to a bowl, mix and keep chillled in the fridge.
Add your black beans, lime juice, cilantro, garlic powder, chili powder and salt to a sauce pan and heat it over medium heat. Begin mashing your ingredients together as they warm up. Then stir in your water until you reach your desired consistency. (You might need to adjust the salt & pepper after adding your water so make sure to taste as you go.)
To assemble: Spread your black beans over the tortillas and top with lettuce, your corn salsa and any other additional toppings. Serve immediately!
