Hello Mari4, welcome to the forum with your first question. Perhaps you could pop over to the Introduce Yourself section on the home page and tell us a little about yourself. How long you've had your TMX etc.
I've had a look around to see if anyone else uses spray, couldn't find anything (that doesn't mean they don't of course) so decided to give it a go myself.
Using 200g red onion, cut into 1/4's, chopped 2 sec/speed 5, scraped down, sprayed the contents for 5 seconds with olive oil spray then sauteed for 4 mins/100o/reverse/speed 1/MC off followed by 2 mins/varoma temp/reverse/speed 1/MC off.
This is how it looks. So, yes you can do it but I think the flavour of a couple of teaspoons of olive oil would add to the end product far more than spray would.
If you have any light calorie meals you make in your TMX, perhaps you'd like to share them with us in the Diet Section.