Bring a large saucepan of cold water to a boil. Add 1 tablespoon salt and trimmed beans. Cook until beans are just tender, about 4 minutes. Remove from heat, drain, and immediately plunge beans into an ice-water bath to stop the cooking process. Drain, pat dry, and place in a large bowl along with ricotta salata and basil leaves.
In a small bowl, whisk together mustard, vinegar, olive oil, remaining 1/4 teaspoon salt, and pepper.
Pour vinaigrette over bean mixture, and toss well.