In a liquid measuring cup or small bowl combine egg whites, the 1/2 teaspoon dill, the salt, and hot pepper sauce. Beat with a fork until combined, but not frothy.
In an 8-inch nonstick skillet with flared sides heat oil over medium-high heat. Pour egg white mixture into skillet. Cook over medium heat. As mixture sets, run a spatula around edges of skillet, lifting egg white mixture so the uncooked portion flows underneath. Continue cooking and lifting edges until egg white mixture is set but is still shiny.
Top half of the omelet with cheese, salmon, and, if desired, broccoli. Lift and fold the unfilled half of omelet over filling. Gently slide omelet out of skillet onto a plate. Sprinkle with additional dill and serve with sour cream.