If you are using fresh morels be sure to clean them in a few changes of warm water. Spin gently to dry and place on absorbent toweling prior to cooking them. This recipe works with a wide variety of mushrooms.
This is a Vietnamese dipping sauce that can be used for many things. It goes by the name Nuoc Cham. To make spring rolls to your liking there are a number of good books on that as well as online sources.