Wash and wipe mango nicely with a cotton cloth such that there is no moisture left . Cut the mangoes to bite size pieces. Discard the seeds.
Take a big cleaned dry glass bottles / pickle containers. Add about 1 tbsp salt into the jar . Add some mango pieces. Again add a tbsp of salt. Add some more pieces and layer with salt. Do this till all your your mango pieces are over .
Cover the lid and keep it aside for atleast 4-5 days . Mix it nicely each day with a clean dry spoon .
Meanwhile Sun dry mustard seeds and chillies for 3-4 hours to make them little crisp. Dry roast them for few seconds
After 4-5 days , you will see that the mango cubes would have turned tender , discoloured and lot of water would have oozed out . Using a strainer separate the mango cubes and water . Keep the salt water aside .
To the separated salt water add 2 more cups water and 1 small fist of rock salt .Heat this up and allow it to boil well till it reduces to almost half . Switch off and allow the salt water to cool .
Now take a clean dry mixer jar . Add sun dried mustard and chillies to it . Make a coarse powder .
Next to the coarse mustard chilli powder add little cooled boiled salt water in steps and grind to get a smooth thick pickle sauce .
Add this pickle sauce the drained mango cubes . Mix well . Add the remaining cooled boiled salt water to the pickle to get the desired consistency . Mix everything well in a wide mixing bowl .
Transfer the pickle to the clean dry airtight storage jar .Let it rest for another 2-3 days so that the mango cubes takes in spices and later you can start using it .
That's it our spicy No oil Cut Mango pickle is ready to enjoy. Store in air tight jar always and use clean spoon. Stays good for 4-5 months without fridge and if refrigerated remains good for years.