Swap in arugula if you like -- simply cook the crust a minute or two more and the topped pizza a minute or two less.
Place a rack in bottom third of oven and preheat to 450°F. Brush bottom of an 11-by-15-inch baking sheet with 1 Tbsp. olive oil. Gently stretch or roll dough to cover sheet. Bake crust until lightly browned, about 4 minutes. Remove from oven,
Scatter spinach leaves evenly over crust, leaving a 1-inch margin. Sprinkle with blue cheese, walnuts and Parmesan. Season with pepper and drizzle with remaining 1 Tbsp. oilve oil.
Bake until cheese has melted and spinach has wilted, about 7 minutes. Slice and serve.