Another lovely find at the Asian market: young coconuts. I thought it was going to be tougher to open, but it wasn't too bad.
Place the coconut on a largish cutting board, or some other large surface to catch all the mess. Take a chef's knife, and peel the soft exterior away from the top of the coconut until a circle (about 3-4" in diameter--bigger than pictured, I had to widen that opening in order to get the meat out) of the hard core is exposed. About 2-3 inches down, hit the core with knife at about a 45 degree angle repeatedly until it cracks. Then use the knife to pry up the top of the shell. Pour the coconut water into a bowl and set aside. Then, with a spoon or a rubber spatula, peel the meat out and place in another bowl/container.
The meat is a lot softer than that of mature coconuts--almost jelly-like. And the water is a lot more flavorful. Delicious, and very filling.