Savory texture garnish description/source?

I believe what you had are known as bubu arare, which are tiny little rice cracker things made of glutinous rice. They are used in Japan as a garnish, sometimes seasoned and sometimes plain. I don't know where you would purchase them, but perhaps the place which sold the app could tell you who their supplier was. Or even be willing to sell you a small amount. The other option might be to use what are called tempura bits or agedama/tenkasu. You can make those at home, yourself - although the size would likely be a bit larger.