Boil 100 grams of chickpeas and 2 medium-sized potatoes. Once cooked, peel the potatoes and mash them. Mix the mashed potatoes and chickpeas together, and add salt, red chili powder, and chaat masala to taste. Set aside.
Prepare the spicy water by blending together 1 cup of fresh mint leaves, 1/2 cup of fresh coriander leaves, 2 green chilies, 1/2 inch piece of ginger, and 1/2 teaspoon of black salt. Add water as needed to make a smooth paste. Strain the paste and add 3 cups of water, 1/4 cup of tamarind pulp, 1/2 teaspoon of roasted cumin powder, and salt to taste. Mix well and refrigerate.
Prepare the sweet tamarind chutney by boiling 1/2 cup of tamarind pulp, 1/4 cup of jaggery, 1/2 teaspoon of roasted cumin powder, 1/2 teaspoon of red chili powder, and salt to taste. Cook until it thickens, then let it cool.
Assemble the panipuri by making a small hole in the top of each puri. Fill each puri with the potato-chickpea mixture, a little sweet tamarind chutney, and top it off with the spicy water.