Im making a cake and don't want it iced. Can i spray edible spray paints straight onto cake?

You could, but it might not look the way you might want. Uncovered cake is tan, brown etc., depending on flavor & degree of doneness. Spraying color over this isn't going to have much impact, color wise, unless it's dark spray color. Using lots of spray color could soak the cake, & that probably isnt going to taste good. And a light spray/shade won't give much color. Naked cakes, or unfrosted cakes, are trendy & popular now, why not leave it plain? I've never seen one spray colored, but maybe you could start a new trend! Perhaps you can trim cooked edges off sides of cake & spray with color & come up with something great. Wilton has a spray that seals crumbs onto cake, I've never tried it, as avoiding mysterious chemicals appeals to me, but it could help seal the trimmed edges. I guess it can't hurt to try, as long as you have some back up cake or some icing to cover if it doesn't work. Best wishes, good luck! And as always, post pics!

shasha 'avoiding mysterious çhemicals appeals to me' too funny and too true

just for the test phase i wonder if you glaze it first -- technically not naked but idk just a maybe -- the color might (?) take better -- just a maybe -- let me/us know what you find out please --

best to you

Its chocolate cake that i want to make black. 

You can spray it but when people eat it it's going to stain everyone's mouths black and taste nasty.

you could use black cocoa for a great result -- i have a photo in my gallery here and it is also a naked cake -- it tastes great -- i buy mine on amazon

and of course i flour the cake pan with it too so there's no white residue

Thanks heaps everybody. Ill try the black cocoa i think.

You could also add black gel color to the batter; this one I saw recently uses both: http://www.sprinklebakes.com/2016/04/black-velvet-nebula-cake.html