Welcome to the Community,
snapshot/delta files contain only changed blocks, so it's rather unpredictable whether, and how much of the data can be recovered.The larger the delta disk the better are chances to recover data. Anyway, first of all it might be a good idea to backup the remaining .vmdk file(s).
The easiest way to access the data in the delta .vmdk might be to:
If you want/need assistance, then please provide as much details as possible. E.g. post a complete list of files (i.e. the output of ls -lisa), and attach the VM's .vmx, .vmsd, and descriptor .vmdk files (the small text files) to a reply post.
Plan B (or even Plan A): If there has not been much activity on the datastroe from which the flat file has been deleted, you may try to contact continuum. He might be able to recover the flat file!