I do not have regular classes. I do them when a group of 4 to 6 approaches me. I do not know where you are. I am in Noida. So in case you have a group do get in touch if Noida suits you.
It is actually a dried yellow chilli. One usually gets the powdered form at provision stores. Since it is not so widely used you may have to ask your shop keeper to get it for you.
Sorry Siladitya, I do not have a recipe for this. I can give you an idea though:
Marinate the duck in salt, pepper, vinegar and worcestershire sauce for a couple of hours. Heat some oil in a pan and brown the whole duck in it over high heat. When brown on all sides, put a cup or so of water, cover and let cook till tender.