Preheat grill to 350 degrees. Once hot, place pineapple on grill and cook for 3 to 4 minutes. Flip over and repeat. Remove from grill and allow to cool before dicing.
Combine all of the ingredients in a large bowl and refrigerate for one hour before serving.
In a shallow bowl or baking disk, whisk together 3 tbsp. olive oil, lime juice, a sprinkling of sea salt and white pepper to taste. Add fish fillets to the marinade. Let fish marinate for 15-20 minutes maximum. Remove fish from the marinade. In a large skillet over medium heat, heat remaining oil. When hot, add fish and cook for 2-3 minutes per side, until tender and flaky. If the fish is so flaky it falls apart, it is still fine to serve in the taco. Serve the fish on warm flour tortillas with pineapple salsa and a drizzle of crème fraîche. Garnish with cilantro and quartered limes.
Makes 4 servings.