How are chenier ridges and strand plains formed at wave dominated coastlines?
The following sources helped me understand these landforms - hopefully they can help you too :)

From the Miranda Shorebird Centre: The Miranda-Kaiaua cheniers are first formed as sand and cockle-shell bars on the foreshore or intertidal flats. The bars are then moved landward by wave action. Eventually the bars attain sufficient height to withstand such wave action.

From NASA's Earth Observatory: Strandplains are built by successive additions of beach sand, usually from some nearby source. Each ridge shows the position of a prior shoreline.