Wash and peel the potatoes, then cut them into long, thin strips. Toss the potato strips well with the cornstarch so they are evenly coated.

Heat oil in a deep pan for frying. Once the oil is hot, add the cornstarch-coated potatoes and fry until golden brown. Remove them and place in a metal strainer to drain excess oil. Fry all the potato strips and keep them in the strainer so any extra oil drips off.

Prepare the sauce for the fried potatoes:

Heat another pan and add 2 tablespoons of oil. Once hot, add the ginger paste and green chilies, and sauté briefly on low heat. Add the chili sauce, tomato ketchup, and soy sauce, and mix well. Dissolve 1 tablespoon of cornstarch in 1/4 cup water until smooth, then add to the pan with the sautéed spices and sauces. Add salt and sugar, and cook for 1-2 minutes. Add the fried potatoes, chili flakes, and vinegar, and mix well. Cook while stirring until everything is well combined. Add half of the chopped cilantro and mix again.

Suggestions:
To make Chilli Potato with onion and garlic flavor, finely chop 1 onion and 6 garlic cloves. Before adding the ginger paste and green chilies to the hot oil, add the chopped onion and garlic and sauté until the onion turns translucent. Then add the ginger paste and all the spices in order, and continue making the Chilli Potato as described above. You can also garnish with finely chopped green onions.