Finely grind nuts, sugar and salt in processor. Blend in flour. Add butter and cut in using on/off turns until butter is in rice-size pieces. Blend in 4 tablespoons ice water, adding more water by tablespoonfuls until dough comes together in moist clumps. Gather dough into ball. Divide in half; flatten into disks. Wrap each in plastic; refrigerate until cold, about 45 minutes. (Can be made 1 day ahead. Let soften slightly at room temperature before rolling out.)
Preheat oven to 400°F. Combine first 5 ingredients in large bowl. Add pears and toss to blend.
Roll out 1 dough disk on lightly floured surface to 12-inch round. Transfer to 9-inch-diameter glass pie dish; fill with pear mixture. Roll out second dough disk on lightly floured surface to 12-inch round; place atop filling. Trim overhang of top and bottom crusts to 1/4 inch; press together and fold under. Crimp edge decoratively. Cut several slits in top crust to allow steam to escape.
Bake pie 20 minutes. Reduce oven temperature to 350°F. Bake pie until juices bubble thickly through vents and crust is golden, about 50 minutes longer. Cool pie on rack 45 minutes. Serve warm or at room temperature.
