Board Thread:Questions and Answers/@comment-172.218.161.237-20150329151728/@comment-27403314-20150425171514

All you have to do is to play any level and match as many green candies as you can. If you had destroyed a certain amount of green candies, you'll get a reward depending on the amount you crushed.

Similar to CC, I also suggest Level 252 as a very neat level for collecting green candies, just get through the blockers and play quickly and the green candies will quickly fill up. I played that level twice and got the final reward with ease. :)