Cowpeas as in Black Eyed Peas - the hulls are edible, but you use them as snaps. I pick them when they are still small and tender. The way I cook a bag of Black eyed peas is by checking that there is not chunks of dirt or tiny rock. Rinse them in cold water, and cook them as you would cook pinto beans. They usually take about an hour depending on how high the burner is set. About half way through cooking them, add the snaps cut into bite size pieces, and then bacon if you like it.
Growing Black Eyed Peas in a small garden - just grow them for the snaps - they freeze very well. Otherwise, it takes a LOT of Black Eyed pea plants to make a pound of dried shelled peas, and it turns into a chore shelling them. Just buy them in the bag - they cost around a dollar.
If you got some in the swap called, "Sugar Snap" you eat them shell and all.
Here's a link to Peas
http://www.rareseeds.com/store/vegetables/peas/
Another for Cowpeas
http://www.rareseeds.com/store/vegetables/cowpeas/
lol, I was typing as Imp was.