Place 2 pounds waxy potatoes and 1 tablespoon of the kosher salt in a large saucepan. Cover by 1 inch with cool water, then bring to a boil over high heat. Reduce the heat to medium and simmer until the potatoes are cooked through and easily pierced with a knife, 15 to 20 minutes.
Meanwhile, thinly slice 5 large stalks celery (about 1 1/2 cups). Thinly slice 3 medium scallions on a slight diagonal (about 1/3 cup). Finely chop 1/2 bunch fresh chives until you have 2 tablespoons. Crumble 2 ounces blue cheese (about 1/2 cup). Place 1/3 cup Buffalo sauce, 1/4 cup mayonnaise, 1/2 teaspoon kosher salt, and 1/4 teaspoon black pepper in a large bowl and whisk to combine.
Drain the cooked potatoes in a colander and rinse under cold water just until cool enough to handle but still warm. Quarter the potatoes, transfer to the sauce, and toss to coat. Add the celery, scallions (reserving some for garnish), and chives, and toss lightly to combine. Taste and season with more kosher salt and black pepper as needed. Top with the blue cheese and reserved scallions. Serve warm or at room temperature.