Cook and mash potatoes.
Grind onion, ginger, green chillies without water (in malayalam-chathakuka).
Heat oil in a pan or kadai.
Saute this grinded items for 6 mins.
Switch off the flame and put the mashed potatoes in it and mix thoroughly.
Put some oil in a kadai.
Put the tuna along with turmeric powder, vinegar and pepper powder.
Saute it in high flame for 2 - 3 mins.
:- This is to just remove the smell of tuna fish. DONT LET THE FISH FRY.
Mix this fish along with the above potato mixture.
Add coriander leaves.
Make into cutlet shapes.
Beat the eggs thoroughly.
Roll the cutlet first in egg and then in bread crumbs and fry.