Process the beans in a food processor until they form a paste. Add the Roasted Garlic and pulse 2 to 3 times to incorporate. Add the tahini, cumin, coriander, paprika and cayenne and blend until a smooth texture starts to develop, 1 to 2 minutes. With the motor running, pour in the olive oil and blend until smooth. The mixture will be thick at this point. Pour in the lemon juice and, if needed, drizzle in water, 1 tablespoon at a time (up to 1/2 cup), until the desired consistency is reached. Season with salt and pepper to taste.
Cover and refrigerate until chilled, about 1 hour. Serve with pita bread, pita chips or fresh vegetables.
Preheat the oven to 350 degrees F.
Cut the top off of the garlic head, exposing the cloves but leaving the head intact. Set the head on a large piece of foil, drizzle with the olive oil and season with salt and pepper. Wrap up the foil to make a pouch and bake until the garlic is soft and roasted, 45 minutes to 1 hour. Set aside to cool. Yield: 1 head garlic