Crispy Parmesan Biscuits

Name: Crispy Parmesan Biscuits
Ingredients: 1 1/2 cups all-purpose flour; 1/2 cup stone-ground cornmeal; 1/2 teaspoon fine sea salt; 2 teaspoons baking powder; 1 teaspoon baking soda; 2 ounces (1/2 stick) unsalted butter, cut into 1/2-inch cubes; 2 cups (5 1/2 ounces) grated Parmesan; 1/2 cup finely chopped green onions; 3/4 cup buttermilk; 1/3 cup olive oil; 1/2 cup Lemon Butter, at room temperature, recipe follows; 3 cups baby arugula; 10 ounces smoked salmon or prosciutto; 1/2 cup (1 stick) unsalted butter, at room temperature; 1 lemon, zested