Wash the mango well. Peel it, slice thinly, and discard the kernel.In a large bowl, soak the mango slices for about an hour with the salt. Add the amba powder and red paprika. Mix and add water. Mix until a slightly thick mixture is obtained. If too thick to drop from a spoon, thin with a little warm water.
Transfer the mixture to a sterilized jar and leave in a sunny place for 2 or 3 days, turning the jar once a day.
Taste to see if all the flavors are absorbed; if not, allow to sit another day or two.
Notes
Choose large, under-ripe mangoes, not ripe, soft ones.