I am assuming you want a clean drive with no partitions on the SSD, correct?
Open an elevated command prompt in Windows. If you have the latest version of Windows 10 it will be powershell. I don't know if powershell recognizes the diskpart command. If not you can change the powershell prompt to command prompt in Windows 10.
Press the Windows key + X > command as admin
Type the following commands
select disk X Where X is the number associated with your external SSD. Make sure you are selecting the correct disk as the next step will wipe it
clean Deletes all partitions on the disk
At this point you should have no partitions on the disk.
Edited by JohnC_21, 07 February 2018 - 10:28 PM.