Heat 1tsp oil in a small sauce pan, fry the green chilies briefly until the skins crackle, about 1-2 minutes.
Grind sesame seeds, mango pieces, green chilies and salt to a smooth paste without adding any water.
Remove chutney into a bowl.
Heat 2tsp oil and add the tempering ingredients and once the seeds start to splutter, add it to the chutney and serve.