Combine the apples and juice in a small bowl, insuring that the apples are covered by the juice. Allow to soak for 20 minutes.
While the apples soak, bring a large pot of water to a boil. Set a medium bowl of ice water next to the stove to use as an ice water bath.
Combine tapioca flour, sugar and salt in a large bowl. Drain the juice off the apples and pour apples into tapioca mixture, tossing to evenly coat the pieces. Shake off the excess tapioca mixture and gently drop the coated apples into boiling water. Allow to boil until coating becomes transparent, about 5 minutes. Remove from the boiling water and quickly dunk in ice water bath.
Drain the apples and divide into four small serving bowls. Pour 1/2 cup of coconut milk into each bowl. Top each with crushed ice. Serve immediately.