What is the white sauce with raw onions in it that is eaten with raw salmon?

I see this a lot in mukbang content so I actually have no idea if this is a common sauce outside of that context but it features in lots of raw salmon mukbang videos made by Korean Youtubers. I’m linking an example but it’s possible this is an obvious one and people already know what it is: https://www.youtube.com/watch?v=N62jBPWFDu8

I would love a name and a recipe if anyone knows of any. Thank you!

by _potatoesofdefiance_