Heat the coconut oil in a large pot over medium heat. Add the diced onion and cook for 4 to 5 minutes until it softens.
Stir in the minced garlic and ginger and cook for 1 minute until fragrant.
Add the Thai red curry paste and stir for 30 seconds to coat the vegetables.
Pour in the rinsed lentils, coconut milk, and vegetable broth. Bring the mixture to a simmer, then reduce the heat and cook for 15 minutes, stirring occasionally.
Add the sliced bell peppers and continue simmering for another 5 minutes until the lentils are tender and the peppers are just softened.
Remove the pot from the heat. Stir in the lime juice and season with salt. Ladle into bowls and top with fresh cilantro.