“Use your imagination—you don’t have to color in the lines,” Sasha Bikoff says of redecorating. The New York–based interior designer known for her playful upholstery choices has a penchant for revamping midcentury Italian and French furniture with remnants of luxe fabrics from fashion houses such as Pucci, Dolce & Gabbana, Oscar de la Renta, and Chanel. Bikoff, whose projects recently outgrew her Tribeca basement, just opened an antiques showroom down the street that offers her own colorful…