Mix water and sugar in a large skillet. Place over medium heat and allow to simmer.
Slice 1/2" off the top of each tomato. Carefully, scoop out the interior of each tomato, placing the flesh into a strainer over a bowl. Leave the outer walls of the tomatoes intact. Press the tomato pulp through the strainer with the back of a spoon.
Peel pears and dice very small. Add almonds and cinnamon.
Split vanilla bean lengthwise. Scrape out the seeds and add to the pears; place the now-empty vanilla pod into the cooking caramel with the star anise.
Add orange and lemon zests to pears. Add juice of 1/2 orange, and the tomato liquid to pears.
When caramel is brown and thick, remove from heat and add 2 1/2 c orange juice. Return to heat and allow to simmer until caramel dissolves into orange juice. Remove vanilla bean pod and star anise pods and discard.
Stuff tomato shells with pears. Pack tightly and allow to overflow a little. Spoon a little caramel sauce into each tomato. Top with reserved tomato slices.
Pour a little caramel sauce in the bottom of a large baking dish. Place tomatoes in dish and pour remaining sauce over. Bake in preheated 350F oven for 10 minutes. Baste with caramel sauce and cook another 15 minutes. Serve with vanilla ice cream.