I am making this request out of fault of my own where I spawned the "fireball" exclusive emoji on someone who ended up having an epileptic episode. Not with malicious intent, though learned the hard way. An error I deeply regret now where a little fun ended up causing a serious effect on someone.
It should be possible to disable any and all emojis on a per-user basis, much like how we can hide any avatar globally, the same should apply to emojis since there is no feasible way to report any problematic emojis (I have seen plenty of emojis that include a 18+ nature, gore, distressing etc)
I understand that emojis can be disabled through the Shield settings however I don't think this applies on VRChat-approved emojis, only user-submitted ones.