Meanwhile, using a zester, remove 1 tablespoon long, thin shreds of peel from orange. Peel pears, leaving stems intact if possible. Cut pears in half lengthwise and use a small spoon to carefully scoop out seeds.
Lay pears in pan with the sugar water, add orange peel and cranberries, cover, reduce heat, and simmer gently until pears are tender when pierced, about 15 minutes; carefully turn pears over halfway through cooking time. Let fruit and poaching liquid cool to room temperature (reserve poaching liquid).
Meanwhile, with a sharp knife, cut away and discard remaining peel and white membrane from orange. Cut between segments to release fruit. Add orange segments to cooled pears, then cover and chill up to 1 day; discard vanilla bean pod.
With an electric mixer, beat cream and 2 tablespoons of the poaching liquid until mixture holds soft peaks.
To serve pavlova, spoon whipped cream into a serving bowl. Set meringues on a platter. With a slotted spoon, lift pears from poaching liquid and lay on a cutting board. Starting just below stem end, cut pears lengthwise into 1/4 -inch slices, leaving them attached at stem end. Use a spatula to carefully transfer pears to a separate platter; gently fan slices apart.
Spoon cranberries, orange peel, and some of the poaching liquid over and around pears. Allow guests to top meringues with fruit and whipped cream to taste. Strain any remaining poaching liquid, and store in the refrigerator to use in place of simple syrup in cocktails or other recipes.