Grind raw, unwashed rice in a blender on high speed to a fine powder. Transfer to a medium bowl and whisk in 4 cups water, vanilla bean and cinnamon stick. Cover and let sit at room temperature for 8 hours and up to 24.
Vigorously whisk rice mixture until rice is evenly distributed and strain through a fine mesh sieve into a 13” x 9” baking dish, pressing on solids to extract as much liquid as possible (you should have about 2 ½ cups). Reserve solids for another use (like cream-of-rice porridge). Whisk milk, sugar and ¼ teaspoon salt into rice milk until completely dissolved.
Freeze rice mixture until edges begin to set, 30–35 minutes. Using a fork, scrape to break up frozen portions. Freeze, scraping and breaking up every 20–30 minutes, until mixture resembles fluffy shaved ice, 2–4 hours.
Meanwhile, toss mango, kiwi, pineapple, pinch salt and remaining 1 tablespoon sugar in a medium bowl. Cover and chill until ready to serve.
To serve, divide granita among bowls; top with fruit and sesame seeds.
Do Ahead: Granita can be made 1 week ahead. Cover and keep frozen. Scrape to fluff just before serving.