Heat a heavy based saucepan over medium heat and add oil. When hot, add onion, ginger, garlic, chilli, 1 tsp sea salt and cumin and cook for 10 minutes, stirring occasionally until onion is soft.
Add lentils and 750 mls of water and cook, stirring occasionally, for 40 minutes over medium-low heat until lentils have dissolved. Keep an eye on the moisture level and add more water depending on desired consistency.
Remove from heat and stir through lime juice. Top with coriander leaves.