Place water (or pineapple juice) and crushed ice in blender.
Add the cubed pineapple, sliced banana, and a pinch of salt.
Cover and mix until blended and creamy, about a minute.
Pour into glass and top with the optional blueberries.
*Blueberry version: Use a bigger blender.Follow quantity suggestions mentioned above and place water, crushed ice, pineapple, banana, and sea salt in the blender. Add 1/2 cup blueberries. Cover and mix until blended and creamy, about a minute.