Toss the kiwis, tomatoes, scallions and cilantro together in a medium bowl. Stir in the lime juice, 1 tablespoon of the oil, 1/2 teaspoon salt and 1/4 teaspoon pepper. If the kiwis are very tart, add the sugar. Set aside.
Mix the remaining 1 teaspoon oil with the cumin, chipotle and 1/2 teaspoon salt in a small bowl. Line a rimmed baking sheet with foil and mist with nonstick cooking spray. Place the salmon, skin side down, evenly spaced on the pan and brush with the spice mixture. Broil until just cooked through, about 5 minutes.
Transfer the salmon with a spatula to 4 dinner plates, lightly sprinkle with salt and top with the relish and its juices.