Put the blue potatoes in a medium saucepan and the Yukon Gold potatoes in a large saucepan and cover both with water. Bring to a boil and simmer the potatoes until just tender, about 15 minutes for the blues and 20 minutes for the Yukon Golds. Drain the potatoes and let cool to room temperature. Peel and cut into 1/2-inch dice.
In a large bowl, whisk the mayonnaise with the lemon juice, relish, cocktail onions, salt, dill and pepper. Fold in the potatoes, celery, red onion and 1/2 cup of chives. Refrigerate the potato salad until cold.
Spoon the potato salad onto a platter and garnish with chives and paprika. Serve cold or slightly chilled, with lemon wedges.