How do you finely dice an onion without crying? This question addresses onion crying

But no one seems to say what should you do when you finely chop an onion. See, not cutting the onion core, using the Gordon Ramsay technique and generally pivoting away from the onion helped so far. But now I have upped my dicing skills. I can chop finer, but alas I am a victim of my own success where the smell of the fine onion is almost like the obscenity of grated onion (horrible).

Sharp knife, not cutting to the core, pivoting away etc all stop working when you are good enough to fine dice an onion. Short of goggles, what do you do?
Breathe through your mouth.

The tear-causing chemicals in onions are absorbed through the nasal mucous membrane. By breathing through your mouth, they don't get much contact with the fumes and won't absorb nearly as much.