Add pecans, 2 tablespoons balsamic vinegar, cinnamon, and cayenne pepper to a skillet. Heat over medium for 3-4 minutes, stirring constantly, until the pecans are toasted.
Add 1 tablespoon granulated sugar and continue cooking for 2 minutes, stirring constantly. Spread pecans onto a piece of foil in a single layer and allow them to cool.
Whisk together the remaining 2 tablespoons balsamic vinegar, remaining 2 tablespoons granulated sugar, Dijon mustard, olive oil, and salt until well combined.
Place spring mix onto a serving platter or in a large serving bowl. Arrange the thinly sliced pear over the greens.
Drizzle with balsamic dressing and top with the cooled pecans and shredded Parmesan cheese. Serve immediately.
Notes
For the best texture, assemble and dress the salad right before serving. The pecans and dressing can be prepared ahead, but wait to slice the pear and dress the spring mix until close to mealtime.