Macaroni Salad With Ham - With legumes

8 ounces elbow macaroni , cooked until firm-tender 3/4 cup mayonnaise (not salad dressing) 1/4 cup plain yogurt 2 tablespoons cider vinegar 1 tablespoon Dijon[...]

1/4 medium red onion , minced 2 teaspoons kosher salt , plus additional for salting water 8 ounces elbow macaroni (about 2 cups) 2 tablespoons milk 2[...]

3 quarts boiling water 1 tablespoon salt 8 ounces elbow macaroni 10 ounces frozen peas, cooked, drained 1 cup diagonally sliced celery 1 cup snipped scallion[...]