Peel and cut oranges into chunks and place in medium mixing bowl. Squeeze any extra juice out of the flesh remaining in the rinds. (Zest orange if you wish to add some zest to dressing)
Core unpeeled apples and chop into small bite sized chunks. Add to bowl and toss to coat with orange juice.
Add all of the remaining fruit and marshmallows to the bowl and mix. (I suggest that if you are not going to serve this within a couple of hours, reserve the marshmallows and add them just before serving)
In another small bowl, whisk all of the dressing ingredients well. Add optional zest if desired. Taste and adjust flavors.
Pour dressing over fruit in mixing bowl and mix gently. Refrigerate until serving.
You can also add some toasted chopped nuts of your choice if you like. They add a little crunch.