1. Add oil to the ground paste and mix well.
2. Coat each cube of fish with the ground paste.
3. Wrap the coated fish cubes in banana leaves. Tie with thread. 
4. Place the wrapped packets in a single layer in a 10" quiche dish.  Micro, covered, for 8 mins. on High, turning once. Let stand covered for 5 mins.
5. Serve wrapped in banana leaves.

*Combine 400 gms. tamarind with 1&1/4 cups hot water and Micro uncovered for 6 mins. on High, stirring once after 4 mins. Remove and let stand covered for 5 mins. Mash to loosen the pulp and separate the seeds.  Pass the tamarind pulp through a fine sieve.

Image: Flickr/creativecommons scaredy_kat