You need to find out the device node of the drive first, you can't format it based on the mountpoint. If you put this drive's information into the fstab file, then just look there to see what the device is. You can also quickly scan for attached storage devices with "fdisk -l".
After you have found the drive (for example purposes, we will assume /dev/sda1, which would be the first partition on the first USB device) you would use a command like:
Code:
mkdosfs -n Data -F 32 /dev/sda1
This would format the device to FAT32 and give it the volume name of "Data". Obviously, be sure there is nothing on this device you need before you reformat it.