If you're making the candied pecans, preheat the oven to 300°F. Line a large baking sheet with parchment paper and set aside.
Add the large egg white to a bowl and beat or whisk thoroughly for 1-2 minutes, until frothy. Add the ground cinnamon, vanilla, salt and maple syrup to the egg white and gently stir. Add the pecans and fold them in until pecans are fully coated.
Pour pecans onto the prepared baking sheet. Spread into an even layer and bake in the preheated oven for 20-25 minutes, stirring halfway through for even baking. Remove from the oven and allow to cool on the baking sheet for 15 minutes, or until pecans harden.
While the pecans are cooling, prep the salad. Add the spinach to a large bowl then top with the strawberries, red onion, candied pecans and crumbled feta cheese. Set aside.
To make the dressing, add all of the ingredients to a medium glass jar with a lid. Close the lid and shake the dressing until it all combines. Pour over the prepared dressing and serve immediately.