Peel the bananas and cut them into halves or thirds, depending on their size.
In a large pot, combine the coconut milk, sugar, salt, vanilla extract, and ground cinnamon (if using).
Heat the mixture over medium heat, stirring occasionally, until the sugar is dissolved and the mixture begins to simmer.
Gently add the banana pieces to the simmering coconut milk mixture.
Reduce the heat to low and simmer for about 10-15 minutes, or until the bananas are tender and heated through. Stir occasionally to prevent the mixture from sticking to the bottom of the pot.
Remove the pot from the heat and let the Vai Siaine cool slightly.
Enjoy your meal!