Heat the olive oil in a small pot over medium heat. Add the chopped onion and sauté until soft and translucent, but not browned, about 4-5 minutes.
Add the peas and the water, cover and bring to a boil. Let this cook 5 minutes, then drain the peas and onions.
Put the peas and onions into the bowl of a food processor and add all the remaining ingredients. Pulse until you have a rough purée. Serve chilled.
Serves 4-6 as an appetizer.