Using a sharp knife, slice the shrimp in half lengthwise through the back divot so you have two thin shrimp fillets. Place the butterflied shrimp in a flat shallow dish or bowl. Pour ½ cup of the lime juice over the shrimp. If it doesn’t cover the shrimp, toss them around so that at least every piece has been coated in the acid. Arrange in an even layer and season generously with salt.
Cover and chill in the refrigerator while you prep the rest of ingredients.
In a blender or food processor, puree the jalapenos, cilantro, grapeseed oil, ½ teaspoon salt and the remaining ½ cup of lime juice until you have a smooth dressing. Taste for seasoning and adding more salt as necessary. Since the shrimp will release some moisture, it’s best to air on the side of too salty (it will get diluted later).
Remove the shrimp from the fridge – they should be beginning to turn light pink. Toss them again if there are pieces not submerged. Return to an even layer and pour half the jalapeno chile mixture over the shrimp. Layer the serrano, cucumbers and onions over the top. Cover and return to the fridge for at least 30 minutes.
Preheat the oven to 400 degrees. On a sheet pan arrange the tortillas and brush them on both sides with olive oil. Bake in the oven until browned and crispy, about 10 minutes. Season with salt.
Garnish the aguachile with the cilantro. Arrange the crispy tortillas and avocado on a platter. To assemble, top each crispy tortilla with ¼ of the avocado slices and some of the aguachile. Use a slotted spoon so that the tortilla doesn’t get too soggy and serve the remaining dressing on the side for additional heat.