Heat oil to 350 degrees. Drop dry puris a few at a time, they will fry up very quickly. Remove and cool.
Mix 2 tablespoons of spice packet with 4 cups cold water, tamarind, and large sprig mint. Set aside and let steep for at least 2 hours.
Peel potatoes and place in a medium saucepan filled with water. Boil until potatoes are fully cooked through. Drain and mash with chickpeas. Season with salt.
Wash and chiffonade herbs. Strain tamarind spice water.
Pop a hole in the puri, and add a scoop of potato/chickpea mixture. Top with a sprinkle of cucumber, red onion, and herbs. Pour tamarind spice water into puri and pop it in your mouth!