Recover multibit.wallet data
Is the wallet encrypted or not ?
If encrypted, then you will have some automatically generated exports of your private keys in the $HOME/MultiBit/multibit-data/key-backup directory. They are encrypted with your wallet password.

You can create a new wallet and import this file using Tools | Import private key.

There are also rolling backups (essentially old versions of your wallet) in the directory rolling-backup that you can open using File | Open wallet