They are served as a side dish in Japanese restaurants but they are wonderful to snack on, especially if you have some garlic salt to hand!
I can't really describe the taste but they are very addictive. I do not like beans, peas, etc because of their "fluffy" texture but these don't have that, they are more... waxy? I got frozen ones from Waitrose and cooked them the night before (4 mins in the microwave, IIRC).