Put the water and salt in a small pan,bring to a boil
add the shrimp and cook for only 15-30 seconds.
Immediately stop the cooking process by dropping
the shrimp in ice water.Do not overcook the shrimp.
Put the drained shrimp in a bowl and add the vinegar,
onions,garlic and peppercorns.Mix well.Cover the bowl
with plastic wrap and marinate for at least 2 hours.
Marinate for 2-3 days in the refrigerator will allow the
flavor to mellow.