Olympic skater Mirai Nagasu was a familiar figure at her parents' Arcadia restaurant when she was growing up

The woman wearing spectacles, clutching an order pad, quietly glided up to diners and bowed. “Please, where do you prefer?” she asked, her voice a whisper. “So sorry we don’t have much space."

It was dinner time at Sushi Kiyosuzu in Arcadia — with servers offering Saturday night specials of sautéed...