I think he was just kidding around. My boyfriend and I do that all the time. "I'm gonna punch you bitch!" "Nu uh ho, Imma punch you first!" and then there are tiny punches. And I wouldn't say Rinoa likes him just for his looks. That's probably part of why she picked him out for the dance, but it's quite clear she's not very fond of him because of his attitude from when they meet in Timber until he saves her in Deling City.