Cut squash in half lengthwise; remove and discard seeds and strings.
In a 2-quart baking dish, arrange two squash halves, cut sides down; add in 2 tablespoons of the water. Cover with vented plastic wrap. Microwave 7 to 10 minutes or until squash is just tender; keep warm. Repeat with the remaining squash halves.
Meanwhile, in a large skillet, cook sausage over medium-high heat for 6 minutes or until browned, adding rice, 1/2 cup of the cheese, sage, thyme, and black pepper in the last 2 minutes of cooking.
To serve, fill squash halves with sausage mixture. Sprinkle with remaining 1/4 cup cheese and drizzle with balsamic vinegar.
