Check out this pummelo candy that my sister gave me.
It was pretty good. Sweet and tart, it was a piece of preserved pummelo skin with sugar. Nice citrus shout-out.
Also, check out this spot, Aji Ichiban, on Mott st. in Chinatown. Where you can get candies like these and many more. This place is also known as munchies paradise, living up to its name with samples of almost every item they carry. Try different dried fruits of various flavors, include several citrus candies.
Plus it's right down the block from Joe's Shanghai, where you can grab some delicious soup dumplings and a crispy spring roll before tucking into your gummy coke bottles on the train ride home.