Heat oil in a pan.

Add tuna to it cook for a few minutes, till it starts turning slightly brown.

Transfer tuna to a plate and keep in fridge to cool.

When cooled, add mayo, chopped onion, celery and chillies to the tuna.

Add salt and pepper to the mix.

Chill the mixture.

Toast the bread slices.

Place the tuna mixture in between the bread to make a sandwich.

Add lettuce, tomato and more red onion to taste.

:- Use the salad within 1 day. :- Chilling it makes it taste better. :- This works for chicken too. Cook the chicken in a pressure cooker with little salt, shred it and use like tuna.