Preheat oven to 400 degrees.
Combine spices for salmon including brown sugar, paprika, salt, chili powder, garlic powder, onion powder, and black pepper. Sprinkle on salmon in an even layer. Let sit for 20 minutes.
Meanwhile, heat ¼ cup olive oil in a medium saucepan over medium heat. Add lemon with the cut side facing down and cook until browned and slightly charred, about 5 minutes. Remove from heat and pour the olive oil into a bowl. Squeeze lemon juice into the same bowl, discarding the lemons. Add chopped parsley, basil, and chives to the lemon oil mixture and season with salt and pepper. Set aside.
Roast the salmon for 12-15 minutes or until flesh flakes easily with a fork. Let rest for 10 minutes.
Prepare pineapple. Combine sugar and cinnamon in a small bowl. Lay pineapple in an even layer on a baking sheet and sprinkle cinnamon sugar mixture on both sides. Bake for 10 minutes. Flip pineapple over and bake for another 10 minutes or until caramelized.
Transfer salmon to a serving platter and drizzle the charred lemon dressing on top followed by caramelized pineapple. Serve immediately.