Later in a Kadai, dry roast the sesame seeds till it splutters. Make sure to keep the flame on medium else sesame seeds might burn and chutney will turn bitter.
Heat oil in a Kadai. When the oil is hot, add urad dal, curry leaves and red chillies. Fry on medium heat, till dal turns golden. Take out on a plate to cool.
Transfer the fried masala, roated sesame seeds ,coconut ,tamarind and salt to a mixer / blender. Grind to a smooth paste...but don't make super smooth. Taste test .
Prepare the tempering. Heat oil in a small pan. When the oil is hot, add mustard. After it splutters add curry leaves and hing. Now pour this tempering on ground chutney.
Serve Sesame seeds chutney with hot rice / idli / dosa / pundi gatti etc . Stays good for 3-4 days in fridge .