Wash and peel the potatoes. Boil in a large pot of salted water until cooked, approximately 20 minutes.
Meanwhile, heat 2 T. peanut oil in a large skillet over medium-high heat. Stir-fry the cashews until they are toasted and slightly browned, about 5 minutes. Remove the cashews, season them with salt and pepper, and set aside.
Add the remaining oil to the pan and heat it to medium. Add the celery and onion and saute until the vegetables are almost tender, about 8 minutes. Add one chile pepper (the other is reserved for garnish), garlic, ginger, curry powder, tumeric, and cayenne. Saute the mixture until the spices are toasted and the garlic is cooked, about 2 minutes. Remove from heat and stir in the sugar and 1/2 of the cashews, reserving the other half for garnish.
When the potatoes are cooked through, drained, and cool enough to handle (but still warm), cut them in half and then into half-rounds. Toss the warm potatoes with the warm curry mixture. Allow the potatoes to cool thoroughly.
Gently stir in the chopped egg, 1/4 Cup chopped parsley (reserving the other 1/4 Cup for garnish), mayonnaise, and salt and pepper. Taste for seasoning and adjust accordingly. Add more mayonnaise if the mixture is too dry.
Garnish with the remaining ingredients: one sliced chile pepper, 1/2 Cup toasted cashews, 2 sliced eggs, 1/4 Cup chopped parsley, and the reserved celery leaves. Sprinkle with paprika if desired.