In a medium sized pan, pour the oil and heat under high heat.
After 1 minute, add the onions, garlic, and salt.
Fry until onion and garlic are slightly turning gold.
(not all the way golden) Add the chillies and continue frying.
Keep stirring the whole time to avoid burning on the bottom of pan.
When the onions and garlic look golden, but not browned, add chilli powder, turmeric and tuna (make sure you drain the liquid out of the tuna can).
Stir the ingredients well for about 1 minute or so.
Lower the heat to the lowest it can go.
Now add the cabbage to the rest of the ingredients in the pot and gently stir around until the cabbage is fully coated with the rest of the ingredients.
Place a lid on the pot and let it cook for about 30 minutes (every 10 mins, stir the mixture, making sure it's not sticking or burning on the bottom of the pan.) Taste and see if the cabbage is cooked after 30 minutes.
If not, leave it for another 5 min or so until you think its cooked.
Goes well with rice or naan, or just as a side dish.