This achievement may or may not need to be grinded after completing the game. Only the blocks that you hit DIRECTLY with Chewbacca count towards this achievement. The best level to grind this on is Level 2-11. You get three Chewbacca birds and there is a bunch of easy-to-break ice blocks. Pause and restart the level as soon as the Chewbacca comes to a stop and isn't going to destroy any more blocks. You can get between 10-20 blocks per attempt of the level, earning around 50 blocks per minute. This grind will only take a couple of minutes at most.