To make a seven-bean salad, bring a pot of water to a boil. Add 2 cups of fresh green beans with the ends trimmed and 1 1/2 cups of thawed frozen edamame. Cook the beans over low heat for one minute. Add 2 cups of snow peas and 1 cup of fresh green peas, and cook for an additional minute.
Drain the beans and peas, then submerge them in an ice-water bath to halt the cooking. Drain them, and allow them to dry. Rinse and drain 1 1/2 cups each of canned chickpeas, baby lima beans and cannellini beans, and combine them in a large bowl. Toss in 1 tablespoon of chopped fresh flat-leaf parsley, 2 teaspoons of fresh thyme and 1 teaspoon of lemon zest. Mix in the cooked and dried peas and beans, and season the salad with kosher salt to taste, approximately 1/4 teaspoon.
To make the dressing, add 6 tablespoons of olive oil, 3 tablespoons of champagne vinegar and 1 teaspoon of Dijon mustard to a food processor. Process them with 1 minced small clove of garlic, 1 teaspoon of mustard seeds, 1/2 teaspoon of lemon zest, 1/2 teaspoon of kosher salt and 1/4 teaspoon of freshly ground black pepper until the ingredients are thoroughly incorporated.
Toss the dressing and the bean salad together, and cover and refrigerate it until serving.