Aguachiles

Directions

1. 1
   You will need to butterfly and devein your shrimp. Using a sharp knife, cut each shrimp lengthwise along the back. For larger shrimp, cut them cleanly into two halves. For smaller shrimp, do not cut all the way through so that the two halves stay together. Once open, remove the gray line of guts running through the center of the shrimp.
2. 2
   In a blender, add the chilies, lime juice, cilantro, and the first teaspoon of salt. Blend until the chilies are just broken up. Don't worry about making a smooth paste. A few chunks of chili are not a problem.
3. 3
   Cover the shellfish with the blended sauce. Marinate in the refrigerator for 15 - 20 minutes. You will know it's done when the surface of the shellfish begins to turn opaque and white. If the sauce does not completely cover the shellfish, stir the mixture after about 5 minutes to ensure it marinates evenly.
4. 4
   While the shellfish is marinating, peel the cucumber and scrape out the seeds. Cut into 1/2 inch cubes.
5. 5
   To serve Add the cucumber to the bowl of shellfish and toss to combine. Spoon the shellfish, cucumber and sauce into a large flat serving dish. Sprinkle with the remaining 1/4 teaspoon salt. Top with the sliced onions and serve with tostadas and sliced avocados.