Green Beans and Summer Squash Salad

Ingredients

• 1 lb. green beans, trimmed and cut into 1½-inch pieces
• 3 tablespoons white balsamic vinegar
• 1 shallot, finely chopped (2 tablespoons)
• 2 teaspoons Dijon mustard
• 2 cloves garlic, minced
• 8 cups rainbow chard, torn
• 1 15-oz. can no-salt-added red kidney beans, rinsed and drained
• 1 medium yellow summer squash, halved lengthwise and very thinly sliced
• Sea salt
• freshly ground black pepper
• ¼ cup chopped walnuts, toasted