Preheat the oven to 400°F.
In a medium pot with a steamer basket, add 1 inch of water and the potatoes. Bring to a simmer, cover, and cook for 8 to 10 minutes, or until fork-tender. Drain the potatoes and let cool slightly.
In a large mixing bowl, combine the remaining potato salad ingredients. Fold in the potatoes and adjust seasoning.
In a small bowl, combine the blackening seasoning ingredients. Coat the salmon with the spice mix and arrange on a baking sheet. Roast for 12-15 minutes, until cooked through.
To make the coleslaw, combine the mustard, mayonnaise, vinegar, sugar, salt and pepper in a large bowl. Fold in the cabbage, onion and carrots.
Combine all of the tartar sauce ingredients in a bowl. Season to taste.
To serve, place each salmon filet on a hot dog bun. Top with tomato slices, arugula and tartar sauce. Serve with potato salad on the side.