Heat olive oil in a medium skillet over medium heat. Add onion slices to skillet and cook for about 25 minutes, stirring every couple of minutes.Meanwhile, add all other hummus ingredients (except water) to the bowl of a food processor and set aside until onion slices are ready.Once onion slices are caramelized, allow them to cool slightly. Then add them to the food processor bowl with the other hummus ingredients. (if desired, reserve a small amount of onions for garnishing hummus)Process ingredients until smooth. Add water as needed for desired consistency. (I didn't need any water for my hummus)Transfer hummus to a serving bowl and garnish with additional caramelized onion slices. Serve with pita chips and/or raw veggies or use as a spread for wraps and sandwiches.