I'll throw in with the traditionalists on this one. When I wear sandals and kilt together, I either A) wear no socks at all or B) wear a pair of gray hiking socks that aren't too tall. I just don't like the look of pulled up kilt hose with anything other than dress shoes.
By the way, don't feel obligated to wear flashes. A lot of us don't wear them except in more formal situations, and with sandals I think they would be over the top.

As stated previously, you'll get a wide diversity of opinions here, and this is just mine.

Welcome to the fray.