Hi,
Thanks for your email.
As far as I know, there's no collection of Jewish music for dulcimer, but I'd love to see one. I know Jessica Comeau is among players who has at least one Jewish song in her repertoire. My setting of Hinei Ma Tov is my album Three Strings and the Truth: New Music for Mountain Dulcimer. It's out of print (the label folded), but it streams on many sources. I've performed other Jewish songs as well.
I'm a composer (and Jewish) and have composed and performed a great deal of Jewish music. Thanks for asking about this. I hope someone rises to meet the challenge.
Best,