In the Android app, tapping on my own comments should offer me a menu with the option to edit or delete the comment. (The edit option persists after 5 minutes, which it shouldn't, but that's something else.)
This menu only works for me on my main site, the Judaism site. On other sites, like Meta.SO or SU, I get the option to vote up (which doesn't work).
This is because it does a simple check for my main site's userid (883). This is obviously different on different sites. However, it does give me the option to edit or delete on every site's user 883.
I didn't try. Maybe I should. You know. For science.