Put all the ingredients (except for the tempering agents!) together in a large bowl and combine well so that everything is evenly mixed.
Next, put the tadka (tempering) together. Heat the oil in a tadka dish or very small wok. When it gets hot, add the mustard seeds and allow them to pop, then add the chilli flakes. The chilli flakes may char a little, this is ok, it will add a smoky flavor. Add the asafoetida powder, and pull off heat immediately. Pour the seasoning over the salad and toss well.
If you are unable to source asafoetida powder, the same amount of garlic powder will do.