Some practical info (site visited in April, 2018). The best place to start exploration of the area is a small town of Toubacouta (frequent local buses or sept-place from Kaolack, main road Kaolack - Karang - Gambian border is a basic transportation artery from Senegal to Gambia). Toubacouta has some descent number of hotels / hostels, shops, restaurants so its an ideal base for visiting the area.
The only way to reach Saloum Delta is to take a boat. There are usual two types of trips offered by local people: southbound trip from Toubacouta to Sipo village (typical Delta village located on artificial mounds made of millions of shells). In the village - around 30 huts you can visit any place as well as buy local products (honey, souvenirs). Trip include visiting some canals with mangrove vegetation as well as local birds.
Another trip is a northbound one to the place called "Ile au coquillages diorum". It is also an artificial island made of shells but much higher that Sipo. It also looks much older as there are baobabs trees that seems to be several hundred years old. The island is currently uninhabited. There are some hiking paths (unmarked)
Both trips costs 15.000 CFA each and takes 3-4 hours depending on the time spent in the village / island. During the trips you should have your own protection against the sun (boats are uncovered). Take also plenty of water and some food with you.
Comparing to other places in Senegal it is one of the most interesting area and relatively unchanged. People still rely on fishing and ostrige collection, transportation is done by boats, huts are built from local materials (wood, straw, clay). Mounds made of shells are quite impresive and high.