For the cauliflower tostadas:

1. Preheat oven to 375 degrees F. Line baking sheet with parchment paper.
2. In a food processor, pulse cauliflower to couscous-sized granules. Some florets may not break down. Pull these out and set aside. Transfer cauliflower “couscous” to a microwave-safe bowl and reprocess the larger cauliflower pieces.
3. Microwave cauliflower for two minutes, stir and microwave for another two minutes. Transfer cauliflower to a cheesecloth (or dish towel) and squeeze to drain out any excess liquid.
4. Place the cauliflower back in the bowl and add two eggs, salt and pepper. Mix together until mixture is wet.
5. Transfer 1/4 cup mixture to baking sheet and smooth into a round circle. Repeat 7-8 times (you will need two baking sheets). Bake for 10 minutes. Flip tortillas over and bake for another 6 minutes, or until golden brown.
6. In a cast iron pan (or skillet) over medium heat, press tortillas down into the pan using a spatula, about 30-60 seconds on each side, until browned and crispy.
7. Turn the oven to broil.
8. Sprinkle cheese over each tortilla and place underneath the broiler for about 5 minutes, or until cheese is melted and bubbling.

For the black bean topping:

1. Meanwhile, in a medium-sized bowl, combine black beans, red onion, jalapeno, lime juice, salt, and Sriracha* to taste, and toss to coat.
2. Spoon black bean mixture over top of tortillas.
3. Mash one avocado in a small bowl using fork (and can add a squeeze of lime and pinch of salt if you have extra) and add a dollop over top of black bean mixture.*