Place the potatoes in a large pot and fill pot three-fourths full with water. Bring to a boil and add the kosher salt. Boil gently until potatoes are just tender and can be pierced easily with a fork, about 10 minutes.Drain well in a colander and let cool 10 minutes.Meanwhile, in a large bowl, whisk the olive oil, Dijon mustard, lemon juice, garlic, thyme, red pepper flakes, salt and pepper together, until well incorporated. Once the potatoes are cooled, add them to the dressing and toss to coat.Preheat the broiler and line a baking sheet with unbleached parchment paper (only use parchment paper if it will all be covered with skewers otherwise it may burn) or aluminum foil.Thread 4-5 potato pieces onto 8-10 inch skewers, cut side up. Or make 6-inch skewers with 3 pieces on each. Place on prepared baking sheet.*Place the potatoes in the oven, 6 inches from the heat source, and broil until browned and bubbly, turning halfway through the cooking time, about 6-8 minutes total.