How to Make It
In a large saucepan, cover the drained beans with 2 inches of water. Cover partially and simmer over low heat until tender, about 3 1/2 hours; add more water as needed to keep the beans covered by 2 inches. Drain the beans; reserve 1/2 cup of the cooking water.
In a medium saucepan, cover the potatoes with water and boil over moderately high heat until tender, about 15 minutes. Drain and let cool to warm, then break the potatoes open with your fingers.
Meanwhile, in a small bowl, whisk the miso paste with the lemon zest and juice. Whisk in the olive oil, then add the garlic, onion and parsley and season with salt.
In a large bowl, toss the beans and potatoes with the reserved bean cooking liquid. Add the miso dressing and toss. Season lightly with salt. Garnish with the almonds, arugula and cheese and serve.