The first step is to prepare your shrimp. In this recipe, using peeled and deveined shrimp is simpler. Add all the shrimp to a food processor and pulse until the shrimp are chopped into small pieces.
To prepare the ceviche, start by adding all the shrimp to a bowl. Juice four limes and pour the juice over the shrimp, ensuring that it is enough to cover them completely. This allows the shrimp to "cook" in the lime juice. Place the bowl in the refrigerator and let the shrimp marinate for at least two hours. After this time, the shrimp should turn slightly pink and no longer be translucent.
Next, chop all of your veggies- cilantro, serrano, and green onion and set them aside. In the food processor pulse the tomatillos until you result in a chunky consistency.
Drain the lime juice that the shrimp was cooked in, and add the juice of two limes along with all the vegetables and mix well.
To assemble the tostada, you would take a little mayo and spread it on the tostada add your ceviche, and top it with some delicious avocado. I like my tostada spicy so I add a little Tapatio hot sauce.