Finnick catches the can and looks at it briefly to determine what it is - not that he recognizes any brands just yet. This one looks familiar though, so he thinks he knows what it'll taste like.

But before he does that, he takes the young man's hand and shakes it confidently despite its largeness and greenness, still offering his friendly smile. "Finnick."

He had thought about a codename. It didn't seem necessary, given that Katniss was running around calling herself the Mockingjay. Anonymity was a lost cause.