Pour the fava beans and the chickpeas together into a colander to drain. Rinse the beans in cold water.
Transfer the rinsed, drained beans to a medium saucepan over medium heat, and add 1 and half cups of cold water. Season with cumin and kosher salt.
Bring mixture to a boil. Reduce heat to low and let simmer uncovered for 20 minutes until most of the water is absorbed, smashing occasionally with the back of a wooden spoon to get the desired consistency.
Meanwhile, combine all the ingredients for the sauce in a small bowl.
When the beans and chickpeas are done cooking, serve the sauce on top or next to the ful medames. You can have stir half the sauce with the bean mixture and serve the other half on the side.
Serve with fresh parsley on top along with warm pita, tomatoes and radishes.