Combine everything except the shrimp in a large measuring cup and stir to combine, Place shrimp in a lidded container (I find a 1 quart canning jar works great) and pour the pickling mixture over the shrimp, making sure the shrimp are covered completely. Cover the container and refrigerate overnight.
To serve, remove the shrimp from the picking mixture and mound on a platter - garnish with cilantro, lime slices, sliced shallots and jalapeno slices if desired.
Shrimp can be made up to two days ahead.
Notes
Fish sauce can be found in many Asian grocery stores or in some well stocked grocery stores.