[quote author=paralleloscope]
How long are you supposed to leave them in?
[/quote]
Not long, until the crust is nice and crispy (2-3 minutes or so).
[quote author=paralleloscope]
and how to get batter to stick on the onion (more rice milk?)
[/quote]
The onions must be dry, and the batter mustn't be too runny.
[quote author=paralleloscope]
Just made a test one, the batter was barely holding to the onion and it instantaneously turned black in the grapeseed oil, what could be the problem?
[/quote]
I think your oil was too hot. Sorry for the confusion about the oil being 'really hot'.
[quote author=paralleloscope]
... aye fire!!! put a towl on but every time i take it off, it brushes up again .. help!
[/quote]
Your oil was too hot, if it caught fire. When oil catches fire, put the lid on to kill the oxygen, and take it off the heat to cool down, without removing the lid!!