Preheat the oven to 450 degrees F. Grease a rimmed baking sheet with nonstick spray.
Stretch the dough into a rectangle on the greased baking sheet. Mix together the butter and 1 1/2 tablespoons bagel seasoning, then spread along the outside edge of the dough. Bake until the crust is golden brown, 10 to 12 minutes. Let cool completely.
Using a rubber spatula, spread the cream cheese evenly over the pizza, leaving the crust edge exposed. Top with smoked salmon, avocado and red onion. Sprinkle with chives, dill and the remaining 1/2 tablespoon everything bagel seasoning.