The thing with onion making people crying is that it's full of methionine/cystine that form sulfuric acid when in contact with the air. Of course, it is only in very small quantities, but it's enough to cause an irritation of the eyes.
If you want to avoid that problem, cut your onion close to the tap with water on. That will be enough to take away the sulfuric acid away from your eyes.
The thing with onion making people crying is that it's full of metionione/cystine that form sulfuric acid when in contact with the air. Of course, it is only in very small quantities, but it's enough to cause an irritation of the eyes.
If you want to avoid that problem, cut your onion close to the tap with water on. That will be enough to take away the sulfuric acid away from your eyes.