Shop Banana Republic's Onia &#124 Chelsea One-Piece Swimsuit: ONIA: Minimal and meticulously crafted, New York-based Onia was founded in 2009 to redefine luxury swimwear. Focusing on high quality, technical materials in innovative fits and timeless styles, every Onia piece is designed to be soft, comfortable and flattering from the first wear., CHELSEA: A fresh take on a classic balconette suit, the Chelsea One Piece has a corset-like design with vertical seaming and lightly padded…