Preheat the oven to 350 degrees F.
Place the walnuts on a sheet tray and cook until toasted, 8 to 10 minutes, and then cool to handle. Chop the walnuts and reserve.
In a medium bowl combine the olive oil, miso, vinegar, honey and a pinch of pepper. Whisk until well blended. Taste, and adjust the seasoning with salt and more pepper if necessary.
In a large bowl combine the greens, pears, feta and toasted walnuts. Add the dressing and toss to evenly coat. Transfer the salad to serving plates and serve immediately.