Preheat oven to 350 degrees. Sift flour, baking soda, and salt into a bowl; set aside.
Put sugars and lemon zest in the bowl of an electric mixer fitted with the paddle attachment. Mix on medium speed 30 seconds. Add butter; mix until pale and fluffy, about 1 minute. Mix in eggs, 1 at a time. Reduce speed; gradually add flour mixture, and mix until just combined.
Scoop dough using a 2-inch ice cream scoop; space cookies 2 inches apart on parchment-lined baking sheets. Flatten cookies slightly with a spatula. Sprinkle tops with sanding sugar, then lightly brush with a wet pastry brush; sprinkle with more sanding sugar.
Bake cookies until golden, about 15 minutes. Let cool on sheets on wire racks for 5 minutes. Transfer cookies to racks using a spatula; let cool completely. Cookies can be stored in an airtight container at room temperature up to 3 days.