Place the rice, dates, cinnamon sticks, vanilla extract, 2 cups of water, and 2 cups of non-dairy milk (use dairy if you like!) in a blender and pulse until the rice is chopped up and incorporated into the liquid (1-2 minutes). Place the mixture in a bowl or pitcher, cover and let it soak in the refrigerator overnight.
Blend the rice mixture in the blender again, pureeing it until it's smooth (1-2 minutes). Strain the mixture into a separate bowl with a fine mesh sieve to remove larger chunks of rice and the cinnamon sticks. Rinse the blender to remove any additional leftover debris then pour the mixture back in the blender and add the pineapple, coconut milk, maple syrup, rum and ice. Blend the mixture until it's smooth and frothy (about 30 seconds).
Pour into 8 rocks-glasses and garnish with slices of pineapple and a dash of cinnamon each.