In a large bowl combine the seeded and diced tomatoes, chopped shrimp, green onion, quartered mozzarella balls, and chopped artichoke hearts.
In a smaller bowl whisk together the minced garlic, salt and pepper, lemon juice, pesto and grated parmesan cheese.
Carefully stir together the shrimp and tomato mixture with the pesto mixture. Cover and place in the refrigerator while toasting baguette slices.
Preheat oven to 375 degrees F. Slice baguette into 1/4 inch thick pieces and lay them in an even layer on a baking sheet or baking stone. Using a pastry brush, brush a small amount of olive oil on each side of each piece of bread. Bake for approximately 8-10 minutes, or until lightly golden. Remove from oven and transfer to a platter for serving.
When ready to serve, peel and chop the avocado into small cubes and add to shrimp mixture. Carefully spoon a small spoonful onto the top of each piece of toasted baguette and drizzle with balsamic glaze (if desired).