Mix onion, chili, ginger, pepper and salt. Squeeze the mixture well to make sure the tastes of the different ingredients blend together.
Add the tuna and mix, squeezing gently, before adding the potatoes. The mixture should now be a thick paste-like mixture.
Add salt, turmeric powder, baking powder and egg into the flour for the batter. Gradually add the water and mix to form a thick batter.
Shape the tuna mixture into small balls and put in the batter.
Use a spoon to scoop up the tuna balls from the batter and into the heated oil.
Deep fry, drain and serve.
Serving Size 10 - 12 people