Wrap the potatoes in aluminum foil and place on preheated bbq or oven for 10 minutes on medium high heat. Place the kale and fennel in a bowl. Mix the mayonnaise, mustard, vinegar, juice, and shredded garlic. Add salt and pepper to taste. Once the potatoes have cooled enough to touch, cut into 3-4mm slices and add to the bowl. Toss the veggies with the dressing. Serve.