In pot soak beans overnight in water to cover generously. Next day, drain beans, cover with fresh water and bring to boil.
Add salt, coriander, cumin and turmeric. Simmer until beans are just tender, about 30 to 45 minutes.
Heat oil in deep saucepan. Add onion, garlic, ginger and cumin.
Fry 10 minutes and add tomato. Cook another 5 minutes and add lobia (black eyed beans) and cooking liquid. Continue to simmer, uncovered, until lobhia are soft but not completely dissolved.
Mixture should be soupy.