Scrub potatoes; cut each in half. In large kettle or Dutch oven, cover potatoes with cold water; add salt. Bring to a boil, covered, over high heat. Reduce heat; simmer until tender when pierced with a fork (10-15 minutes); drain. Transfer to large bowl. Add Lemon Vinaigrette and red onion; toss to coat. Refrigerate, covered, several hours or overnight.