In a saucepan, mix together the cornstarch, sugar, and salt.
Whisk in the coconut milk and simmer over medium-low heat, stirring constantly until the mixture thickens and is thoroughly cooked through, about 6 to 7 minutes.
Remove the saucepan from the heat and pour the pudding into individual dessert cups or ramekins.
Allow the pudding to cool off a bit before placing it in the refrigerator for at least 1 hour.
Garnish with ground cinnamon and/or toasted coconut flakes before serving.