To roast garlic, preheat oven to 400 degrees F. Slice 1/2 inch from the top of the garlic to expose pods. Place garlic in the center of a 6" x 6" piece of aluminum foil, top with 1 tablespoon of olive oil and 1/2 teaspoon of salt. Wrap tightly in foil, place on a baking sheet and roast 1–1 and 1/2 hours or until garlic is soft. Remove from oven and cool. Squeeze the roasted head firmly to remove all of the roasted garlic and set aside, discarding peels. In a small bowl, combine lemon juice and water and set aside. In a separate glass bowl, whisk together tahini and 3 tablespoons of olive oil then set aside. Reserve 1/4 cup of whole chickpeas for garnish. In the bowl of a food processor, add remaining chickpeas, roasted garlic, cumin, cayenne and remaining salt then process 15–20 seconds. Using a rubber spatula, scrape down the sides of the processor and blend 1 additional minute. With the processor running, add lemon and water mixture through the feeder tube in a slow, steady stream until well blended. Add tahini and oil mixture in the same fashion and process 15–20 seconds or until well combined. Add cilantro and pulse 2 seconds, but do not purée. Transfer mixture to a decorative bowl, drizzle with remaining olive oil and top with reserved whole chickpeas. Serve hummus as a dipping sauce with warm pita bread, chips or grilled shrimp.