Add the ground beef and onions to a skillet over medium high heat. Saute until the meat is browned completely, and the onions are softened. Drain the excess grease.
Reduce the heat to medium, and stir in the cream cheese, ketchup, dijon, worcestershire sauce, garlic and salt and pepper to taste. Saute until the cheese is melted and the ingredients are well combined.
Preheat the oven to 400 degrees.
Slice the zucchini in half lengthwise, and use a spoon to scoop out the center of each half.
Place the zucchini halves into a well greased 9x13 baking dish.
Fill the zucchini halves with the meat mixture.
Bake for 20 minutes.
Remove, and top with the shredded cheddar. Bake for an additional 10-15 minutes.
Top with the cherry tomatoes and bacon pieces before serving.