Put the chickpeas, artichoke hearts, tahini, garlic, lemon juice and olive oil into the bowl of a food processor or a high speed blender.
Process until very smooth, about a minute or so. Open the machine and scrape down the sides. Run the machine again and add the cold water through the top. Add salt to taste.
Spoon onto a shallow bowl, and drizzle with olive oil. Scatter a few chickpeas over the top. Serve with pita chips or raw veggies for dipping.