In a bowl, add whole wheat flour and salt. Add water and oil and knead into a soft yet firm dough. Rest the dough for 15 mins.
Rinse the radish, peel and grate. To the grated radish, add salt and mix well. Set this aside for 10 mins. Radish will release a lot of water.
After 10 mins, squeeze out the water using a cheesecloth. Note - quantity of radish will reduce in half.
To this, add red chili powder, fresh green chilies and coriander leaves. Mix and divide into equal portions.
Divide the whole wheat flour dough into equal portions. Dust the surface with some flour and roll out the paratha. Add a portion of the stuffing, cover and roll the paratha carefully by dusting the surface with enough flour to prevent sticking.
Heat a cast iron flat griddle. Once hot, add the rolled out paratha. Let it cook on one side (brown spots should appear), smear some ghee. Flip and cook the paratha on the other side in the same manner.
Once paratha is cooked on both sides, remove from hot griddle and serve.