Preheat oven to 350 degrees.
Coat 24 regular size muffin cups with nonfat cooking spray. Using a long knife, cut the apples into small pieces while they are still in the can. (This saves time and also saves having to clean another dish.) In a medium bowl, mix the apples, water and 1 tsp. cinnamon until well blended. Stir in the cake mix until well mixed. Fill the prepared muffin tins half full. Mix the Splenda with the remaining cinnamon. Sprinkle the mixture lightly over the tops of the muffins before baking. Bake for 20 minutes or until a toothpick inserted in teh center of a muffin comes out clean.