i wish ao3 would let me see where i've left kudos... is there a way to do that?
There is currently no way to search for the fics that you've Kudo'd . Kudos aren't tracked except to tell you you've already left one on a fic. The best bet is to bookmark fics you like or to save for later.
There is a Reddit post on a way to add a user script that would allow you to see your kudo'd fics but I've personally never used it so try it at your own risk here I think it's only for a computer browser, but again I've never used it.
Your best bet would be to petition ao3 for it, they do update the website with new things (ex bookmarks sorted by updated, block users etc), so it might be a thing we get in the future just not right now.
TL:DR: No, maybe if you use a computer? But also it could be a thing in the future.
Link to My ao3 guide