Preheat outdoor grill if using to medium high. Prepare hot grill with cooking spray. Indoors, use a large skillet rather than a grill pan and preheat with a drizzle of extra-virgin olive oil to medium-high heat. Place 1-½ lbs skinless salmon fillets, cut into large chunks in food processor and pulse to coarse grind meat to form burgers. Transfer fish to a mixing bowl and season with 1 tbsp grill seasoning, (recommended: Montreal Seasoning by McCormick), 1 tbsp poppy seeds, 1 tbsp sesame seeds, and 3 tbsp chopped fresh dill. Mix and form 4 patties. Drizzle the burgers with extra-virgin olive oil. Cook burgers 3 minutes on each side for a pink center, 4 to 5 minutes on each side for fully cooked fish. While burgers cook, combine in a bowl 1/2 cup softened cream cheese and the 3 scallions, whites and greens, chopped and fold in sour cream and 1 tsp lemon juice. Top the burgers with lettuce, tomato, red onion and sauce on crusty kaiser rolls, split and toasted.