Make the caramel: Toast the sesame seeds in a skillet over medium heat until golden. Transfer to a dish. Remove the peel from the orange in wide strips, then squeeze the orange juice into a separate dish; set aside.
Cook the sugar in a skillet over medium heat, swirling the pan, until deep amber. Whisk in the butter, cream and salt until dissolved. Add the orange peel and juice. Cook, whisking, until the sauce thickens, 5 to 10 minutes. Remove from the heat. Add the sesame seeds. (You can refrigerate the sauce, covered, up to 1 day; reheat before serving.)
Make the fritters: Bring 4 cups milk, the salt and cinnamon to a simmer in a saucepan over medium-high heat. Add the rice, reduce the heat to medium, and cook, stirring, until tender, 20 to 25 minutes. Add the condensed milk and 2 tablespoons sugar; cook, stirring, until thick, 5 to 10 more minutes. Stir in the vanilla and let cool completely.
Roll tablespoonfuls of the rice mixture into balls. Put on a parchment paper-lined baking sheet; cover and chill until ready to fry.
Make the batter: Whisk the flour, baking powder and the remaining 2 tablespoons sugar in a bowl. Whisk the egg and the remaining 3/4 cup milk in a liquid measuring cup; gradually whisk into the flour mixture until smooth.
Heat 2 inches vegetable oil in a wide saucepan until a deep-fry thermometer registers 350degrees F. Working in batches, dip the rice balls in the batter using a fork, then fry until golden, turning once, about 8 minutes per batch. (Return the oil to 350degrees F between batches.) Drain on paper towels. Drizzle with the caramel.