Heres a simple dressing:

1:Get some juice from lime. lemon and several oranges
(modify orange ratio depending on how sweet you want your dressing, or even add honey if allowed)

2: Add some grated fresh ginger and some grated fresh garlic to taste.
3: Add some extra virgin olive oil (I usually do 1 part citrus to 2 parts oil)
4: Salt & Pepper to taste.

A good spring dressing!