Heat oil in large skillet over medium-high heat. Add onions and cook 3 minutes, or until translucent. Add garlic, green curry paste, curry powder and salt. Stir to combine.
Add broth, water, and coconut milk. Bring to a boil and add lentils. Reduce heat, cover and simmer, stirring occasionally, 30-40 minutes, or until lentils are cooked through.