Cook snap peas in boiling salted water in a medium saucepan over high heat until crisp-tender, 1 to 2 minutes. Drain and run under cold water until cool. Slice in half.
Arrange Mache, eggs, pea shoots, edamame, avocado, cucumber, bell pepper, pepitas, and snap peas on a serving platter. Season with black pepper.
Serve with Green Goddess Dressing.
To make the Green Goddess Dressing, process ⅔ cup plain Greek yogurt, ⅓ cup firmly packed fresh flat-leaf parsley leaves, 1 chopped scallion, 1 ½ tablespoons fresh dill, 1 ½ tablespoons firmly packed fresh tarragon, 1 ½ tablespoons olive oil, 1 tablespoon each lemon zest and lemon juice, and 1 small garlic clove in a food processor or blender until smooth, about 30 seconds. Season with salt and freshly ground black pepper.