1. If using bacon, cut the bacon into 1/2-inch pieces and cook in a skillet over medium heat, stirring occasionally. As the bacon starts to brown, reduce heat to low to prevent the bacon from burning and continue to cook until it is crispy and brown. Use a slotted spoon to transfer to a small bowl and set aside.

2. Place a pot of water for the pasta on the stovetop. Cook the pasta according to the package directions. Drain and rinse with cold water to stop the cooking process.

3. In a large bowl, toss the pasta with dressing and chill in the refrigerator for 5-10 minutes.

4. Just before serving, add the bacon or tuna, avocado, tomato, and any of the optional ingredients. Toss and serve immediately.