Place potatoes and salt in a large pot and cover with cold water. Bring to a boil, then reduce to a simmer. Cook for 8–10 minutes or until fork-tender. Drain and let cool completely.
2 pounds Russet or Yukon Gold Potatoes, 1 teaspoon Salt
Cool the potatoes: Drain the potatoes and pour onto a baking sheet to cool before assembly the salad.
In a small bowl, whisk together the mayo, Dijon mustard, vinegar, garlic powder, salt, and pepper.
1 cup Mayonnaise, 1 Tablespoon Dijon Mustard, 1 Tablespoon Vinegar, ½ teaspoon Garlic Powder, ½ teaspoon Salt, ½ teaspoon Black Pepper
In a large mixing bowl, gently toss the cooled potatoes with the tuna, chopped eggs, celery, onion, and pickles. Pour the dressing over the top and gently stir to combine.
2 5 ounce cans Tuna, 3 Hard-boiled Eggs, ½ cup Celery, ⅓ cup Red Onion, ¼ cup Sweet Relish, 1-2 Tablespoon Fresh Dill
Cover and refrigerate for at least 30 minutes to let the flavors come together. Add extra mayo just before serving if it seems a little dry.