How to Make It
Cook pasta according to package directions, adding 4 teaspoons of the salt to boiling water. Drain pasta, and rinse in cold water; set aside.
While pasta cooks, whisk together mayonnaise, lemon juice, mustard, 3/4 teaspoon of the salt, and 1/2 teaspoon of the pepper in a large bowl. Toss pasta with dressing.
Add romaine, tomatoes, bacon, avocado, and remaining 1/4 teaspoon each salt and pepper to the pasta; toss to combine. Chill 20 to 30 minutes before serving.