Heat oven to 450 degrees F with the rack in the lowest position. Heat oil in a 10″ skillet over medium heat. Add spinach and garlic and cook until wilted and liquid has evaporated, 3 to 4 minutes; transfer to a plate. Cool skillet slightly and wipe clean.
Stir together ricotta, Parmesan, lemon juice, and red pepper flakes in a bowl. Season with salt and black pepper. Sprinkle skillet with cornmeal. Stretch dough into a 12″ round. Carefully press dough into the bottom and up the sides of the skillet.
Top dough with ricotta mixture, spinach, Cheese, and artichokes. Bake until the crust is golden brown, 20 to 24 minutes. Let stand 5 minutes.