くうかい？
杏子ちゃんです。さやかの王子様です

Wanna Eat?
It's Kyouko-chan. She's kind of like Sayaka's prince.

I think in this case くうかい？ is 'Hungry?' or literally 'Wanna eat it?'

I thought it was that too, but I wasn't sure so googled it to see how it was used in other ways and it seemed to mainly come up as "regret". They both make sense for Kyouko, but I'd agree that the "hungry" meaning fits her face here more. I've changed it now.