Make dessert rub: mix sugar, cinnamon and a pinch salt.
Leaving the skins on, cut each banana length wise and then again in half crosswise.
Sprinkle the rub onto the cut sides of the banana and let sit for 5 minutes.
Grill them, cut side down, on a very clean cooking grate on medium-low direct heat just long enough to get grill marks, about 1-2 minutes.
Turn them over with a pair of tongs and move them to an area of the grill with indirect heat (let them continue to cook, slowly, while having dinner). When the skin starts to pull away from the flesh of the banana, they’re finished (you can see when the skin pulls away).
Remove the peel and serve with vanilla ice cream, dulce de leche, and a little sprinkling of the dessert rub.