In a saucepan, combine coconut milk with sugar and salt. Bring to a full boil, and cook for about 6 minutes, stirring occasionally.
In a bowl, combine cornstarch with 3/4 cup of water, and with a whisk, mix well into a slurry.
Immediately pour slurry into saucepan and cook for 2 minutes, continuously whisking until mixture thickens into a pudding.
Remove from heat. Pour mixture through a colander, and transfer the strained pudding into a nonstick 12-inch by 6-inch deep dish or into individual martini glasses.
Smooth out the surface, and set aside to cool. Refrigerate for 2 hours to completely set.
Dust surface with ground cinnamon, slice, and serve.