Cook bacon in large nonstick skillet over medium heat, stirring occasionally, until crisp, about 5 minutes. Remove bacon and reserve 2 tablespoons drippings; set aside.
Cook onion, carrots and celery in reserved drippings over medium-high heat, stirring occasionally, until golden, about 8 minutes. Stir in garlic and cook 30 seconds.
Turn onion mixture into slow cooker. Add 1/2 of the bacon and reserve remaining bacon for garnish. Mash 1/2 cup beans with fork. Stir in beans, tomatoes, Knorr® Chicken flavored Bouillon Cubes and water. Cook covered on LOW 8 to 10 hours or on HIGH 4 to 6 hours. Stir in ditalini and cook covered on HIGH an additional 30 minutes. Serve with reserved bacon and, if desired, grated Parmesan cheese.