Hearthstone was released today for Android phones, so I attempted to install it on my Galaxy S2. When I launched the app for the first time it began unpacking files. This failed partway through, because my device ran out of space (from what I could tell it attempted to unpack everything to the system partition, which is only 2GB). I attempted to run SD Maid in order to free up space, but my phone rebooted while the app was scanning. Now my phone can't get past the SAMSUNG logo when I attempt to power it on. I can boot into CWM recovery and access the device via ADB.
How can I free up the space on my system partition so my device can boot again?