Remove the green peel from the white part of the watermelon rind. Roughly dice the white part. Set it aside
To a heavy work add a spray of oil and roast the urad day and the dry red chilli, till the dal turns golden brown and the red chillies crispy to a snap. Add the flax seeds and saute until some of them crackle.
Now add the diced watermelon rind, chopped tomato, ginger slices and saute for about 5 minutes.
Sprinkle salt and steam for another two minutes so they release water and steam through.
Add in the coriander leaves and take off the heat.
Cool and grind to a smooth paste.
Enjoy with crispy dosa or soft steamed idly