Cook the potatoes: Add the potatoes to a large pot of cold salted water. Keep them whole and unpeeled to avoid soaking them with excess water. Bring to a boil and cook for about 20 minutes, adjusting slightly depending on potato size. Test doneness by piercing with a fork. Drain and allow to cool completely. (I usually do this a few hours before starting the recipe so they are well cooled.)
Preheat the oven to 400°F (200°C fan). Line a large baking tray with parchment paper and lightly brush or spray with olive oil. Spread the potatoes on the tray. Using a sturdy mug or glass, smash the potatoes flat. Generously brush or spray with olive oil. Bake on the top rack for about 30 minutes, or until golden and crispy (see notes).
Prepare the edamame: Place the edamame in a heatproof bowl and cover with boiling water for 5 minutes. Drain and set aside.
Make the peanut sauce: In a small blender, combine the peanut butter, ginger, garlic, lime juice, tamari, maple syrup, soy milk, and Sriracha. Blend until smooth. (Alternatively, finely mince the ginger and garlic and whisk everything together by hand.)
Assemble the salad: In a large serving bowl, combine the edamame, carrot, cucumber, mint, cilantro, scallions, crispy potatoes, chopped peanuts, and peanut sauce. Toss gently and serve immediately for the best texture.
