In a medium mixing bowl, beat sugar, oil, eggs, pumpkin, orange juice, and orange zest. Set aside.
In a large mixing bowl, whisk together the remaining dry ingredients. Pour pumpkin mixture into bowl with dry ingredients, and stir until no lumps remain.
Lightly grease and flour loaf pans or muffin pans. (This recipe will fill about 8 mini loaf pans, OR 3 regular loaf pans, OR 24 muffins.) Fill pans or muffin cups 3/4 full.
Bake in a pre-heated oven at 400 degrees for about 15 minutes (muffins), 20 minutes (mini loaves), or 25-30 minutes (regular loaves). Check with a toothpick or fork (should come out clean).
Remove bread from pans and place on a wire rack to cool, covered with a clean towel. While cooling, mix powdered sugar and cinnamon in a small bowl. Add just enough water to make a glaze. Poke tops of bread with a fork or toothpick, and drizzle the glaze over the warm bread.
Slice bread with a thin serrated knife and serve warm, or allow bread to finish cooling, and store in a sealed bag or container.
*These breads work great for freezing. Just make sure they are wrapped up well.