To remove the flesh of the mango, cut the flesh away from the pit in 2 large pieces. Use a paring knife to cut through the flesh (but not through the peel) in a crisscross grid pattern. Use your thumbs to press against the skin side and pop the mango cubes up. Cut across the bottom, along the peel and add the cubes to the blender.
Peel ginger. Grate ginger finely into bowl. Use fingers to squeeze juice out of gratings. Discard juiced gratings.
Put ginger and remaining ingredients in the blender and blend until thick and smooth.
If you don't have a blender you can still make the drink: Just whisk everything but the ice together in a mixing bowl. Fill glasses with ice and pour the mixture on top.