Melt coconut oil in a large stockpot over medium-high heat, then add curry powder, garlic, and onion. Saute for about 3-4 minutes on medium heat, stirring often so the garlic doesn't burn.
Add vegetable stock and green lentils. Bring soup to a boil, then partially cover and reduce heat. Simmer for between 20 and 50 minutes (or until lentils are tender; mine typically take about 50 minutes).
Once the lentils have finished cooking, remove soup from the heat and stir in the coconut milk and salt. Puree the soup using an immersion blender or regular blender (in batches if using regular blender) until it is as smooth or as chunky as you prefer.