Remove zest from lime in wide strips with a vegetable peeler. Cut lime in half; set aside. Bring zest, garlic, coconut milk, and fish sauce to a simmer in a large skillet over medium heat. Arrange shrimp in skillet in a single layer and cook, maintaining a bare simmer, until opaque and pink, about 6 minutes total, 3 mins/side. Using a slotted spoon, transfer shrimp to a shallow bowl or plate, or place directly on your serving platter and let cool.
Continue to cook coconut milk until it thickens slightly (similar to the consistency of runny honey), about 5 minutes and then remove from heat. Remove and discard lime zest, garlic cloves and any shrimpy bits. Season coconut sauce with kosher salt and pepper and let cool in pan.
Right before serving, squeeze juice from one of the reserved lime halves over the shrimp.
To assemble the dish, place the shrimp on a medium sized platter and then carefully pour (or spoon) the coconut sauce over the shrimp. Top with red onion, jalapeño, tomatoes, and cilantro. Squeeze remaining lime half over. Drizzle with a little olive oil, top with tortilla chips, and sprinkle with kosher salt.
Enjoy this dish either warm, room temp, or cold. Serve as is or over rice, rice noodles or lettuce.
Notes
To avoid soggy crunchies, be sure to wait until right before serving to add the tortilla chips.If using smaller shrimp, decrease the overall cooking time to as little as 3 mins total. Shrimp take very little time to cook.Do ahead: Shrimp can be cooked and coconut sauce can be made 1 day ahead. Transfer to separate airtight containers. Cover and refrigerate until ready to serve.