Green Peppercorns have a milder pepper flavor than black pepper, as they haven't oxidized and their flavor profile is more akin to the flavor you would have if you plucked a fresh underripe peppercorn off the vine and popped it into your mouth.

You can rehydrate Green Peppercorns. Simply add them to your liquid of choice, whether it be water, wine, cooking stock, etc. and let them sit for about an hour. They should puff up a bit  and their surface will be smoother. After they've been rehydrated, they can be used in a variety of recipes.