Trio of Fresh Peas and Scallion Soup

Name: Trio of Fresh Peas and Scallion Soup
Ingredients: 2 cups chicken stock or canned low-sodium broth; 2 cups water; 1 pound English peas, shelled and pods reserved; 6 small scallions, whites thinly sliced and greens coarsely chopped; One 1/4-inch-thick slice fresh ginger; Salt; 1/4 pound sugar snap peas, cut on the diagonal into 1-inch pieces (1 cup); 1/4 pound snow peas, cut into matchsticks (1 cup); 2 ounces soft tofu, cut into 1/4-inch dice (1/2 cup); 1/4 cup cilantro leaves; 1 1/2 teaspoons rice wine vinegar; Freshly ground pepper