Can I see who is the owner of this charging pass is?

When you click on 'passes' in the left menu you can see the list of whitelisted passes and the user which is connected to it.

If the charge pass is unknown or not added to the whitelist we cannot see who the owner is of the charge pass.

FAQ

I see an unknown pass is charging at our charging station. Can I block the charge pass?

It is only possible to block out charging passes when you set the access mode of the charging station on  Whitelisting (Restrict this Location to certain persons only.). Then only charging passes on the whitelist can charge. Be aware that these users will charge for free. 

It is not possible to have the access mode on roaming and block out a charge pass.