There isn’t a command that will list just the ACID and the last used date for all users. TSS LIST(ACIDS) DATA(BASIC) but it will show more than the last used date.
Run a TSSCFILE/TSSCFBK with TSS LIST(ACIDS) DATA(BASIC) and write a program (EARL or SAS) to parse the TSSCFILE/TSSCFBK output and just show the ACID and last used date. The last used date is in record ID 0900.
Columns 15-22 contain the user ACID
Columns 33-40 contain the last used date.
Columns 41-45 contain the time last used.
Columns 46-49 contain the CPU.
Columns 50-57 contain the FAC.
Columns 58-62 contain the COUNT.
NOTE: TSS LIST(ACIDS) … should be done during off-peak hours because it does a lot of I/O to the security file, which can negatively impact performance. (TSSCFBK runs against the backup file so it won’t impact performance.)