Ingredients

• 1/2 cup kosher salt, divided, plus more to taste
• 1 pound small shrimp (51–60 count), peeled, deveined, tails removed
• 3 plum or 2 regular medium tomatoes, seeded, finely chopped
• 1 small (or 1/2 large) white onion, cut into 1/4" cubes, rinsed with cool water, patted dry
• 1/2 English hothouse cucumber, seeded, finely chopped
• 3–4 serrano chiles, stemmed, seeded, deveined, finely chopped
• 2/3 cup fresh lime juice
• 1/2 cup coarsely chopped fresh cilantro
• 24 small corn tortillas or store-bought crispy tostada shells
• Vegetable oil (for frying; if needed)
• Kosher salt (if needed)
• 2 cups Hold-the-Lime Guacamole
• Shredded iceberg lettuce, crema (Mexican salted cream) or sour cream, queso fresco, tomatillo salsa (for serving)
• A candy or deep-fry thermometer

Instructions

1. Fill a large bowl with 10 cups cool water; stir in 1/4 cup salt (it should taste like seawater). Add shrimp and soak 30 minutes, then drain.
2. Fill a medium pot with 8 cups water; stir in 1/4 cup salt. Bring to a boil, add shrimp, and immediately turn off heat. Let sit until pink, opaque, and barely cooked through, about 3 minutes. Drain, transfer to a large bowl, and let cool.
3. Add tomato, onion, cucumber, chiles, lime juice, and cilantro to shrimp. Season with salt. Chill until ready to use.
4. Assemble the tostadas: If frying tortillas, fit a large skillet with candy or deep-fry thermometer; pour in oil to measure 1". Heat over medium-high until thermometer registers 375°F. Fry tortillas in batches until crispy, turning every 30 seconds, about 2 minutes total. Drain on paper towel-lined baking sheets and season with salt. Spread 1 heaping Tbsp. Hold-the-Lime Guacamole on a tostada shell. Top with 1/4 cup shrimp salad, then lettuce, crema, queso fresco, and salsa. Repeat with remaining tostada shells. Serve at room temperature.
5. If frying tortillas, fit a large skillet with candy or deep-fry thermometer; pour in oil to measure 1". Heat over medium-high until thermometer registers 375°F. Fry tortillas in batches until crispy, turning every 30 seconds, about 2 minutes total. Drain on paper towel-lined baking sheets and season with salt.
6. Spread 1 heaping Tbsp. Hold-the-Lime Guacamole on a tostada shell. Top with 1/4 cup shrimp salad, then lettuce, crema, queso fresco, and salsa. Repeat with remaining tostada shells. Serve at room temperature.
7. Do Ahead Shrimp salad can be chilled for up to 1 day. Bring to room temperature before serving.
8. Shrimp salad can be chilled for up to 1 day. Bring to room temperature before serving.