Grind Grated coconut, Garlic, Ginger, Cumin seeds, Curry leaves and Green chilli together and add little salt.
Mix tuna, carrot, 1/2 cup Onion, pepper powder, kudampuli, and 1 tbsp oil together and keep aside.
Heat oil in a pan and add ingredients mustard seeds, cumin seeds, fenugreek and curry leaves one by one.
Add remaining onion and saute till it slightly changes the colour.
Add chopped ginger, garlic and saute for some time.
Add chopped tomatoes and cook it well.
Add the prepared mixture of tuna, carrot and grinded coconut into it.
Cook for about 10 to 15 minutes.
:- Your tune thoran is now ready to serve!!!