In a medium bowl, combine pineapple, tomatoes, cilantro, red onion, jalapeño, lime juice, and salt. Cover and refrigerate until ready to serve.
Position the oven rack in the center position and preheat the oven to 400°F. Lightly grease a baking sheet with nonstick cooking spray.
Place the salmon filet skin-side down on the prepared baking sheet. Drizzle olive oil evenly over the salmon.
In a small bowl, combine chili powder, salt, onion powder, garlic powder, cumin, and sugar. Sprinkle the seasoning mixture evenly over the salmon, gently rubbing it into the surface.
Bake the salmon for 15–18 minutes, or until the fish is flaky and cooked to your preferred doneness. For medium, cook until the internal temperature reaches 130°F.
Serve the salmon warm, topped with pineapple salsa. Squeeze fresh lime juice over the top before serving for extra brightness.