You can do
show security flow session nat
And that will show you what current translations you have. You can also do
show security nat <static|source|destination> rule <rule name|all>
And that will show you the translation hits, etc. that you have for each of your rules. It also shows you what addresses are getting translated (from what pools you have configured, etc.).
You can also append "extensive" and "detail" to some of those commands too, to get more output.
Hope this helps!