In the rich text editor:
@kiemeo
In a comment:
[kiemeo](https://chowlings.com/user/kiemeo)
For Names and Avatars:
In the rich text editor:
%kiemeo
In a comment:
[![kiemeo's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/kiemeo) [kiemeo](https://chowlings.com/user/kiemeo)