wandu is a word of unknown origin. According to Antoine Maduro* some lexicographers viewed it as an indigenous Carib word, others as a word of African source.
Wandu ta un sorto di bonchi. Wandu is a kind of bean.
Wandu is a species of plant in the legume family. "Pigeon pea" appears to be the English name; the scientific name is Cajanus cajan. It makes seeds that can be cooked and eaten. Roasted seeds can make a sort of coffee that was used for medicinal purposes (according to one list of home remedies that I found on the web).
Photos of the plant and its seeds are visible in Wikipedia. About 200 ways to use the plant's seeds, leaves and stems are described in a webpage at purdue.edu
*Procedencia di palabranan papiamentu i otro anotacionnan, Corsou 1966