1. Toast pecans in preheated oven on a baking sheet at 350°F for 10-15 minutes, until toasted and fragrant. Set aside.
2. Keep the oven preheated to 350°F. Line an 8" square pan or a 12" x 5 1/2" pan with parchment paper, leaving enough parchment on the sides to use as "handles" for pulling out the finished bars. Place nuts, oats, dates, cinnamon, and salt in food processor until mixture is coarse and crumbly. Add the apple and pulse in until there are no longer any large chunks left. Continue to process until everything starts to clump together, using a spatula if necessary to help move things around.
3. Transfer the mixture to the lined-prepared pan. Flatten and compact mixture. Make them very flat to ensure an even bake.
4. Bake the bars in the preheated oven for 20 minutes. Cool for 10-15 minutes, and then slice into bars. Once completely cool, lift out of the pan. Store in an airtight container in the fridge.