At iDO, we are using emojis heavily. And we chose the fire 
to represent high priority items through a priority drop down custom fields.
But the problems are:
- this priority can’t be seen easily in Calendar, Timeline or even My Tasks
- the priority of the parent task can’t be seen when looking at a subtask
We obviously needed to store that priority inside the task name, and there was no way we would manually add the emoji.
So we turned to the API (that service allowing you to discuss with Asana servers and read or write whatever you want).
We now have an automation that goes through our tasks every 5 minutes, adding or removing the emoji based on priority!
How cool is that? Let me know if you are interested to get the same thing 
(you can email me at bastien@ido-clarity.com)