Install iFile (search it on Google - cydia)

Go to Home first(the house-icon) and you should see a list of directories.
One of them is called Applications if I'm not mistaken(else try /var/mobile/applications), and you should see a list of folders with names like b465621-kr-45986 and so on, open them all until you've found the blockchain one.

That should contain your wallet info somewhere.

*donate to the IMineCoin app - project development forum*