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