Roast Chicken Salad, Green Beans, Fennel, Potatoes, and Grainy Dijon Vinaigrette

This salad is a riff on a dish I ate at Rochelle Canteen: a chicken salad with the veggies and potatoes all mixed together. Why keep everything isolated, when they can all be steeping in a sharp, grainy mustard dressing? I’ve included instructions for roasting the chicken, but if you’ve got a favorite rotisserie place or just some leftovers, feel free to use that instead.