I could use an app like that.
Looking for an app that shows me who I’ve zapped today? #asknostr
I’ve been #zapping reposters of today’s #FreedomPoll, but lost count of the last one I #zapped. I still have a few more people to #zap… how do I find out who?
Fun fact:
All that zapping put me at 19th place, for total amount zapped so far on nostr today, just ahead of nostr:npub1sn0wdenkukak0d9dfczzeacvhkrgz92ak56egt7vdgzn8pv2wfqqhrjdv9, according to zaplife.lol
nostr:note1c3kajsltc5ttmvp94f5dlejs0caz87t0pe7uns9w9lmpnyqqxvssqd8hwv 
Discussion
Doable but i believe would need to pull all the kind 9735 events, parse the description tag for originating pubkey that created the zap request compared to your pubkey.
To my understanding this is what zaplife does, possibly on an inbound stream routing from peered relays to gather it live and add a tally per pubkey receiver and sender.
Doing as an on demand type of call per pubkey would need to fetch chunks from relays. If you have a specific referenced event in mind, that narrows the data set. For what its worth, the Boost Zapper bot ive been working on tracks each zap it makes both to npub and lightning address.