Whisk the condensed milk, evaporated milk, and 2/3 cup (165 milliliters) water together in a pitcher, making sure to completely combine the two canned milks.
Add the rice and almond flour and whisk again.
Add the cinnamon sticks, cover, and refrigerate for at least 12 and up to 24 hours.
Strain into a bowl, pressing hard on the solids. Discard the solids.
Return the milk mixture to the pitcher. Divide among four tall ice-filled glasses and sprinkle each with ground cinnamon.