In a small saucepan, whisk cream cheese, sour cream, 1 1/2 tsp. dill, lemon juice and white pepper. Heat over medium-low, whisking constantly, until warmed through. Remove from heat.
In a medium skillet, heat the oil over medium; add the eggs. Stir with a spatula, scraping the bottom of the pan, until the eggs are almost set, 1 minute. Reduce the heat to low; spread the eggs evenly over the skillet. Place the scallions, 1/3 cup of the cream cheese mixture and the salmon over half the omelet. When the bottom is set, fold the omelet over. Slide onto a plate and serve with the remaining cream cheese mixture. Sprinkle with dill.