Preheat the grill. Season the chicken with salt, pepper, and 1/2 tablespoon of olive oil. Place the chicken on the grill and cook for about 4 minutes on each side. Using a sharp knife, split the pineapple in half. Using a paring knife, make a slit around the sides of the pineapple, leaving about 1/4-inch trim and remove the fruit. Reserve the pineapple boat. Remove the core from the fruit of the pineapple and cut into 1/2-inch slices. Season the pineapple slices with salt, pepper and remaining olive oil. Place the pineapple slices on the grill and cook for 1 to 2 minutes on each side. Remove from the grill and cool. Reserve 2 slices of the pineapples and dice the rest of the fruit. Dice the cooled chicken. In a mixing bowl, add the two reserved slices of fruit. Using the back of a fork, mash the fruit against the side of the bowl. Add the walnut oil and whisk until emulsified. Stir in the chervil. Season the vinaigrette with salt and pepper. In a mixing bowl, toss the diced chicken, pineapple, red onions, celery, and walnuts with the dressing. Cover the salad and refrigerate for 1 hour. Remove both the pineapple boat and salad from the refrigerator. Spoon the salad into both pineapple boats. Garnish with chopped parsley.