A spunky, sassy, skateboarding girl would be:
Cadi or Leo (Leocadia)
Sadie (Sara or Isadora)
Yeah, mostly nicknames. Rockabilly names would probably work great!
My first and really only thought is Eleni nn Leni. It's super feminine and sleek, but I feel like Leni would be into any type of sports. Soccer, skating, football, basketball, baseball... especially soccer and skating, though. But that's the beauty of Eleni--I feel like Leni could be a skateboarder, but Eleni could be a ballerina. She could really be anyone.
That's really all I've got, though, haha, sorry.