Thank you for your question, keira. '깨알 같다' It's idiomatic phrase, not slang. 깨알 means a grain of sesame seed. Thus '깨알 같다' means 1. Something or someone that is tiny or small like sesame seed. 2. Something that is trivial or small fun. Have a nice day.

Hi Keira, I would say 깨알 같다 means 소소한+detail. You can also use 요소요소/사이사이/곳곳마다. For example, 깨알 같은 재미 means 소소한(+detail) 재미. 깨알 is 깨+알. 깨 is tiny small one of types of nuts. We make sesame oil using that. Hope this help.