System Restore is implemented using the Volume Shadow Copy Service (Volume Snapshot Service, VSS). As such, you can use
vssadmin in an elevated command prompt to list all of the restore points:
vssadmin List Shadows
Note that Windows Backup also uses VSS, with shadow copies stored on both the system and backup drives, so if your backup drive is connected, the shadow copies stored on the backup drive corresponding to these backups will be listed as well. Add
/for=C: to specify the volume you want to list the shadow copies for, replacing
C: with the volume letter of your choice if it is not C:.
While this isn't the easiest way to work with restore points, you can use the creation date and time and shadow copy ID listed in the output from the above command to delete specific restore points, using the
vssadmin Delete Shadows command. You can also create restore points with
vssadmin Create Shadow and change the amount of space available to restore points with
vssadmin Resize ShadowStorage. More information about
vssadmin is available in this TechNet article.