If not using store-bought tostada shells, preheat oven to 400F. Brush both sides of corn tortilla with oil, lay in a single layer on a baking sheet, and lightly sprinkle tortillas with salt. Bake for 10 minutes or until crispy, flipping tortillas halfway through. Alternatively, grill tortillas for about 3 minutes on each side.
Cilantro Lime sauce: whisk together all ingredients in a bowl. Adjust seasonings to your preference. Set aside.
Heat 1 tbsp oil in a nonstick or cast iron skillet over medium-high heat. Once hot, add corn and cook for 8-10 minutes, or until corn starts to brown, stirring occasionally. The more dark bits, the more smoky the corn will be. Remove corn and set aside.
In the same skillet, heat 1 tbsp of olive oil over medium heat. Add the black beans, hot sauce, chili powder, cumin, and salt. Heat until the beans are warm, and then cover to keep warm.
On each tortilla, place black beans, roasted corn, and avocado. Drizzle with tahini sauce, and garnish with jalapeño slices, cilantro, and/or hot sauce. Enjoy!