Wash the rice in several exchanges of water until the water runs clear.
In a large pitcher, combine rice with cinnamon sticks and vanilla extract.
Add boiling water and stir to combine.
Transfer to to refrigerator and leave to soak overnight (or for at at least 4 hours).
Transfer everything from the pitcher to a blender.
Blend really well until the everything is well pureed and smooth.
Pass this mixture through a strainer and return the mixture to the blender.
Add milk, 1 cup water and sweetened condensed milk.
Blend well until thoroughly combined.
Chill or serve over ice, garnished with ground cinnamon.
Always stir before serving, as rice sediment may sink to the bottom as it chills.