Bring water to boil (just enough to cover amount of shrimp you are cooking). Add any spice you are using to water at the beginning. When the water begins to boil, add the shrimp. Let come back to a full boil again. Remove from heat immediately and drain shrimp. Plunge into a bowl of ice water. This will make the shrimp crisp and crunchy. Do not add salt to water as it tends to toughen shrimp. Keep shrimp packed in ice up to 3 days.