How to Make It
In a medium saucepan, cover the potatoes with water and bring to a boil. Season generously with salt and simmer over moderate heat until the potatoes are tender, 15 to 20 minutes. Drain well and let cool, then cut in half.
In a large serving bowl, whisk the mayonnaise with the wine, vinegar and chopped tarragon. Season the dressing with salt and pepper. Add the chicken, fennel and cooled potatoes and toss well. Season generously with salt and pepper and toss again. Garnish with the tarragon leaves and fennel fronds. Serve right away.