Boil brown rice for 25 minutes and drain.
Saute onion in a large saucepan with 2 Tbsp water for 3 minutes.
Place the lentils in saucepan and add 4 cups of water.
Bring to a boil over high heat. Reduce the heat to medium and stir in the ginger and garlic.
Cover the pan and simmer until the lentils are soft and have turned yellow, 15 to 20 minutes.
Add the coriander, turmeric, cumin, and up to 1 cup water if the dahl is very thick. Simmer for about 10 minutes more to blend the flavours.
Boil green beans for about 5 minutes, or until soft yet crisp, then drain.
Stir the lemon juice and fresh coriander into the dahl. Taste and adjust the seasoning. Serve hot, with rice or bread and green beans.