Reserve about one cup of the chickpea water before draining.
Drain the beans and add them to a food processor, along with the tahini paste, lemon juice, salt, a couple tablespoons of olive oil, and the garlic. Puree into a nice smooth paste. Add water along the way as you do not want it to be really thick, but have a lighter texture.
Remove from the processor and plate. During this time cook the fava beans in about 1/4 cup of water. Add a pinch of cumin, along with the chopped tomatoes. Cook for about 25 minutes or until the beans are cooked through and nice and tender.
When you are ready to serve, ladle some hummus onto a plate, add a couple of tablespoons of the fava beans into the center, and drizzle with additional olive oil, lemon juice, a pinch of salt, and shower with chopped parsley. Serve with warmed naan bread.