Place the potatoes into a large pot and cover with salted water. Bring to a boil over high heat, then reduce heat to medium-low, cover, and simmer until tender, about 20 minutes. Drain and allow to steam dry for a minute or two. Allow to cool completely before cutting into bite-size cubes. Transfer to a large bowl
Bring a large pot of salted water to a boil over high heat. Add the asparagus spears, and cook until tender, about 3 minutes depending on size. Drain and immediately plunge into cold water to stop cooking. Cut the asparagus spears into 1 inch pieces. Place in the bowl with the potatoes. Stir in the artichokes, breaking them apart slightly as you put them in the bowl.
Combine the mustard and lemon juice in a bowl; whisk the oil gradually into the mustard and lemon juice until smooth. Season with salt, pepper, and cayenne pepper to taste. Drizzle over the vegetables; toss to coat. Sprinkle with chives to serve.