Make tostada bowls: Preheat oven to 300°F. Brush tortillas on both sides with vegetable oil. Place them in oven safe bowls to create bowl-like shapes. Bake for about 15-20 minutes. Checking occasionally to prevent burning. Remove from oven and keep in the bowl until cool.
In a large bowl, combine chopped lettuce, black beans, tomato, corn, and some lime juice.
To assemble, place the salad in the tostada bowl, top with steak, sour cream, jalapeños, cilantro and hot sauce.