In small saucepan, combine Lentils and 1 1/2 cups water and bring to a boil over high heat. Reduce heat to low, cover and simmer until Lentils are tender and water is absorbed, 35 to 40 minutes. Drain well. Transfer to small bowl. In small food processor or blender, process walnuts and oil to smooth paste. With rubber spatula, scrape mixture into bowl with Lentils. Mash to paste with fork.