Bring a large saucepan of water to a boil and cook the pasta according to the package directions.
Drain, rinse with cold water and set aside.
Cook bacon in a large skillet over medium heat until crisp, about 4 minutes.
Remove the bacon and add the red onion and sauté for 5 minutes.
When the bacon is cooled chop into small pieces.
Add the spinach to a salad bowl.
Add the dandelions and pasta shells.
Add the blue cheese, onion to the mix.
Toss the salad.
Serve with the Blue Cheese & Tomato Dressing.