JackL: thank you for the pointers! I had a whole lot of trouble getting access to MySQL via the command prompt. I kept getting Error 1045: (28000) Access denied for user 'admin'@'localhost' (using password: YES). This on a Windows Server 2003 machine, GoDaddy hosted. But figuring I could work around this using the table names you provided:
4. delete from tts_tickets;
5. delete from tts_tickets_events;
6. delete from tts_reporters;
... and a necessary port number (-P8306) you mention, I decided to use Plesk's hook into phpMyAdmin to get at the MySQL tables GUI-style. From there, I could 'empty' the tables you listed, clearing *all* Help Desk Tickets.
Exactly how I got there in Plesk for Windows 7.5:
Server > Sevices: Databases > [MySQL] tab > Connection: Server name*: localhost : 8306 > Tools : MySQL RootWebAdmin > Database: PSA
(Welcome to phpMyAdmin 2.6.0-pl3)
Scrolling way down the list of tables, then one at a time clicking the trash can on the tables:
tts_tickets
tts_tickets_events
tts_reporters
"Do you really want to: TRUNCATE 'table_name'?"
<OK>
Back into the Help Desk, ALL the dummy/test tickets I created are gone, just as I wanted! But be sure you want to delete all tickets before choosing to 'empty' the tables.