1 pound red-skinned potatoes, unpeeled, cut into 1/2-inch pieces
4 ounces green beans, trimmed and sliced into 1-inch pieces
2 tablespoons whole-grain mustard
2 tablespoons red-wine vinegar
3 tablespoons extra-virgin olive oil
1/2 teaspoon natural cane sugar
Fine-grain sea salt
1 leek, white and tender green parts, trimmed and chopped
1/4 cup finely chopped fresh dill
6 small stalks celery, trimmed and diced
1 cucumber, peeled, seeded, and diced
6 ounces extra-firm tofu, diced
1 tablespoon minced chives