How to find Spam email addresses without opening the Spam Mail?

If you want to see if your email has been pawned by people there is a site where you check to see if might used by spammers ';--have i been pwned?

You could look in Mail but you have to open the email to do which I wish they would change in Mail. If you have a email open look under View in the menu bar and look for Message>All Headers or Raw. I would prefer if we could do this without opening the email.

Not really since spammer are constantly changing either the email address they use or the subject on the email spam. You can block them until water turns to rock and you will still get spam.