1. Heat oven to 450 degrees F.
2. Place potatoes in a large pot and cover with cold water. Bring to a boil. Lower heat and simmer 20 minutes until potatoes are just cooked. Add asparagus and cook for an additional 3 to 4 minutes or until asparagus is tender. Drain; cut potatoes in quarters. Meanwhile, in a medium-size bowl, whisk together brown sugar, vinegar, lemon juice, lime juice, mustard, garlic salt and black pepper.
3. Place salmon in a glass baking dish. Brush 1/4 cup of the sugar-vinegar mixture over the salmon; set remaining mixture aside. Marinate salmon at room temperature for 10 minutes. Bake in 450 degrees F oven for 15 to 18 minutes, or until fish flakes easily.
4. Place warm potatoes and asparagus in a large bowl. Whisk olive oil into remaining sugar-vinegar mixture. Gently toss with the potatoes and asparagus. Fold in tomatoes.
5. Serve potato salad warm or at room temperature with the salmon.