Wash and soak moong / green gram in 2 cups water for 5 hours or overnight.
Separately pressure cook moong along with 2 cups water and 1/2 tsp salt for 2 whistles on high heat. Allow the cooker to cool naturally.
In a wide bowl, mix cooked moong, banana peel slices, salt to taste and tamarind paste/juice. Adjust the consistency with 1/2 cup water. It should be of pouring consistency. Cover with a lid and cook on low to medium heat for 15 minutes or until banana peel slices soften.
Add coconut paste, mix well and cook on a low heat for 8-10 minutes (do not add extra water).
Heat oil in a frying pan. Add mustard seeds. When they splutter, add jeera and curry leaves. Saute for 2-3 minutes until fragrant. Pour the seasoning over the curry and mix well. Serve with rice.