Put oven in middle position and preheat oven to 350°F. Whisk together pumpkin, oil, eggs, pumpkin pie spice (1/2 tsp cinnamon, 1/4 tsp ginger, 1/8 tsp allspice, 1/8 tsp nutmeg, dash cloves), 1 1/4 cups sugar, baking soda, and salt in a large bowl until smooth, then whisk in flour until just combined. Stir together cinnamon and remaining 1 tablespoon sugar in another bowl. Divide batter among muffin cups (each should be about three-fourths full), then sprinkle tops with cinnamon-sugar mixture. Bake until puffed and golden brown and wooden pick or skewer inserted into the center of a muffin comes out clean, 25 to 30 minutes. Cool in pan on a rack five minutes, then transfer muffins from pan to rack and cool to warm or room temperature.