French bread slices go great with this flavorful spread. Alternatively, stuff it into a whole-wheat pita along with paper-thin slices of red onion and crisp romaine lettuce.
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.
On cutting board, cut garlic in half; sprinkle with 1/4 teaspoon salt. With flat side of knife, mash together. Add to lentil-walnut mixture along with arugula, broth, cumin, coriander and remaining 1/4 teaspoon salt. Mix well. Cover and refrigerate up to 4 days.