First, soak the lentils in a bowl of cold water for 2 hours. Drain, rinse, and pour into a blender. Add the water and season with salt. Blend until smooth and pale. Heat a drizzle of oil in a nonstick pan about 15 cm in diameter. Add a ladle of the mixture and spread it evenly over the pan to form a crepe. Cook over medium heat for a couple of minutes, then carefully flip. Cook on the other side and remove from the pan. Repeat until all the mixture is used up, making sure to grease the pan thoroughly. Stuff as desired and serve.