I think you'd lose something by just calling it rice crackers, even without the kakimochi twist. Some of the things are very obscure, but for something like senbei, I think anyone reading this fussy food nerd manga already knows them or is here to learn, and for learning they need to see the name a lot! You can trust your readers a little more. Of course adding the small 'rice cracker ' margin note the first time is great. And you've always got your exhaustive notes in the back, which are great, for if there's any confusion.
Anyhow, purely my opinion, you TL however you feel right, and thank you!