Prepare your ingredients: julienne the onion, jalapeno, ginger, and curry leaves, chop the cilantro and cashews. Add the rice flour to a large skillet and toast for about 5 minutes over medium heat, it will still be white in color. Remove from heat and set aside.
In a large bowl, add the onion and sprinkle the salt over it. Follow with jalapeño, cilantro, ginger, curry leaves, and cashews. Mix until combined.
Add the besan flour, toasted rice flour, cumin, ajwain seeds, chili flakes, oil, and water. Mix until combined— the mixture will be sticky but it should still hold it's shape, if it's running you will need to add more flour.
To a wok over medium-low heat, add about 2" of oil and heat to 350F. When the oil is ready, add about 2 tablespoons of the batter into the oil and fry until golden brown. Remove from oil and drain onto a paper towel.
Serve warm!