Cooking potatoes curry I use my method which is i peeled potates and washed them with water. Then, i cut them and washed them with water again before cook them. Is it right or wrong? Because my aunty said, don't wash them again after cutting. Can you give me suggestions?
When you wash or soak cut potatoes, you are rinsing away a good deal of starch that has come to the surface during and after the cutting process (it's the white stuff that gets on your knife and fingers when cutting). 

In a potato curry, removing this starch by washing the cut pieces can result in a broth that's not as rich or thick, but I would try it both ways to see if it actually makes a notable difference - if your curry tastes watery, washing away the surface starches of the prepped potatoes is to blame.