Did you just stumble upon a file that is digitally signed by Tuna Media Ltd? If that's the case, please read on.
You'll probably see Tuna Media Ltd when double-clicking to run the file. The publisher name is displayed as the "Verified publisher" in the UAC dialog as the screengrab shows:

You can also view the Tuna Media Ltd certificate with the following procedure:
Here's a screenshot of a file that has been digitally signed by Tuna Media Ltd:

As you can see in the screengrab above, the Windows OS reports that "This digital signature is OK". This means that the file has been published by Tuna Media Ltd and that the file has not been tampered with.
If you click the View Certificate button shown in the screenshot above, you can examine all the details of the certificate, such as when it was issued, who issued the certificate, how long it is valid, and so on. You can also see the address for Tuna Media Ltd, such as the street name, city and country.
Go Daddy Secure Certification Authority has issued the Tuna Media Ltd certificates. You can also examine the details of the issuer by clicking the View Certificate button shown in the screenshot above.
The following are the Tuna Media Ltd files I have gathered, thanks to the FreeFixer users.
| Detection Ratio | File Name |
|---|---|
| 0/46 | UNINST_Uninstall_R_93F5911C3DE44D43B806420E6E249E16.exe |
| 0/54 | _8B0EF4715D1A47FEB9C995BB29C513F1.exe |
The detection percentage is based on the fact that I have gathered 100 scan reports for the Tuna Media Ltd files. 0 of these scan reports came up with some sort of detection. You can view the full details of the scan reports by examining the files listed above.
The analysis has been done on certificates with the following serial numbers: