on the contrary, kissers can be very agressive and get quite large. more than large enough to swallow a neon whole. the smaller varieties of gourami should be fine though. most of their agression is directed towards members of their own species.
I had a dwarf gourami in with my 55g w/ neon tetras and I am almost positive he ate 2 of them. Or at least killed them. Just my experience but perhaps I just got a ill-tempered gourami. I have since moved him to his own 6g, all by himself.