Process pecans, flour, and cornstarch in food processor until finely ground. Add remaining ingredients and pulse until dough forms. Turn dough out onto lightly floured surface and roll into two 8-inch logs. Wrap tightly with plastic wrap and refrigerate until firm, at least 1 hour or up to 3 days.
Adjust oven racks to upper-middle and lower-middle positions and heat oven to 400 degrees. Line 2 baking sheets with parchment paper. Slice logs into 1/4-inch rounds and place 3/4 inch apart on prepared baking sheets. Bake until golden, about 15 minutes, switching and rotating baking sheets halfway through baking. Let cool 3 minutes on sheets, then transfer to wire rack and cool completely. Serve. (Rounds can be kept in airtight container at room temperature for up to 3 days.).
Make Ahead: At the end of step 1, logs can be wrapped in plastic, then foil, and frozen for up to 1 month. Defrost in refrigerator before proceeding with step 2.