To delete all OID users, please follow the below steps.
Run ldapsearch to extract the names of all users.
ldapsearch -x -h oidserver.corp.company.com -p 389 -D cn=orcladmin -w passwd -L -b "cn=users,dc=corp,dc=company,dc=com" -s one "objectclass=*" dn > current_users.txt
From the file that is generated, Delete the text dn: (Use find - replace to do this). Also make sure that every entry is in one single line.
Run the ldapdelete to delete all the users from the file.
ldapdelete -x -h oidserver.corp.company.com -p 389 -D cn=orcladmin -w passwd -c -v -f current_users.txt
Login to oidadmin to confirm the delete.
Run the same for cn=Groups to delete all groups.