To make the filling:

Bring a large pot of water to a boil. Add the potatoes, turmeric, and 1 tablespoon of the salt. Reduce the heat to a simmer, cover, and cook until the potatoes are tender but not falling apart, about 25 minutes. Drain, transfer to a large bowl, and set aside.

Heat the oil, mustard seeds, and curry leaves in a large skillet over medium-high heat until the mustard seeds begin to pop, about 1½ minutes. Add the chiles and cook until the curry leaves become brittle, about 1 minute longer. Stir in the ginger and jalapeño, cooking for 30 seconds, and then add the mixture to the potatoes.

Mash the potatoes against the sides of the bowl until they are semismooth. Stir in the remaining 1½ teaspoons salt and the lime juice. Take 2 tablespoons of potato mixture and roll into a small ball, set the ball on a baking sheet, and repeat with the remaining potato mixture.

Heat the canola oil to 350°F in a medium saucepan. To make the batter, whisk together the chickpea flour, cayenne pepper, salt, and asafetida (if using) in a small bowl. Whisk in enough water so it resembles a thick pancake batter. Dip each potato ball in the batter and roll it in your hands to coat evenly. Gently drop a few battered balls into the hot oil and fry until they are golden brown, turning often, for 3 to 5 minutes. Transfer the dumplings to a paper towel-lined plate and serve hot with Tomato Chutney or ketchup.