In a small bowl, combine paprika, garlic powder, onion powder, thyme, salt, and cayenne and mix well. Drizzle each salmon filet with about 1 tsp of olive oil, then sprinkle blackening seasoning equally on each piece. Let sit at room temperature for 30 minutes.
Heat a grill to medium-high heat, then spray lightly with nonstick grill spray. Lay pineapple sliced on a baking tray, then drizzle with about 2 Tbsp olive oil, turning to coat on both sides. Sprinkle with 1 tsp of kosher salt. Grill for 3-4 minutes per side, then remove. Let cool slightly, then core and cut into a small dice.
Place grilled pineapple, avocado, jalapeno, cilantro, and 1 tsp kosher salt in a bowl, and stir to combine. Refrigerate for at least 30 minutes.
Cook salmon on grill over medium-high heat, skin side up, for about 3 minutes. Flip and cook another 2 minutes, or until salmon reaches an internal temperature of about 115 F.
Top salmon with pineapple salsa and eat immediately.