Wash the prawns in running water and then drain.Cut the onions very fine like we cut for egg omlet.Peel and cut the potato in small squre shapes.Finely chop the coriander.Make slits on the green chillies.Roughly chop the tomatoes in lenght wise.Keep all the things aside.
Marinate the prawns with half of the turmeric,redchilly,garlic and salt. Keep aside for 15 minutes.
in a frying pan take 1/2 tbsp of oil and fry the prawns untill done. Keep aside.
In a seperate pan take the rest of the oil and let it be hot, then add methi seeds and leave for 10 to 15 seconds.
Then add the onion in it and cook until transparent.
Then add the green beans and fry it until fully coated with oil then add coriander, red chilly, turmeric and cumin powder fry for one minute then add the garlic paste,salt and little amount of water and fry it untill the oil seperates from it .
Add 1/2 cup of water and cover it. When it starts to boil add the prawns,tomato,green coriander and green chillies. Cover and cook on very low heat until done. There should be no water in the curry,the consistency should be very thick.