Level: Cyclone
Load up the level where you will start off in a snowy courtyard standing face to face with an elite mini boss style enemy. Around the edges of the courtyard you will find a number of snowballs dotted around for you to use. I recommend that you run behind him and use the snowballs on this side as fast as possible as they actually deal a significant amount of damage, especially if he falls as a result of getting hit by one. Eventually some other mobs are going to join in on the fight and will obstruct you from just continuously lobbing snowballs. Try to just work on getting his health as low as possible and try to lure him to a location where you can simply flick a snowball at him using
hopefully killing him and unlocking your achievement.
The level ‘Cyclone’ can be accessed from the fifth batch of new challenges and requires a total of 90 stamps to unlock and play.