On my iPad, the StackExchange app is using over half a Gigabyte. Really? Is that necessary? Can we have an option to flush cached data?
I tried the option to clear the cache (in the Settings app, as suggested by @JAL in his/her answer). On the next app launch it sat at a dark blue, empty screen for about 20 seconds then quit. At the next launch it came up, but the storage usage went down by only 2%, from 653MB to 640MB.
I even tried a force reboot after that (hold
poweroff->AppleLogo->poweroff) but that had no effect.