Preheat oven to 300°F. Line a sheet tray with parchment paper.
In a large bowl, add the aquafaba and beat with an electric hand mixer until foamy. Add pecans and brown sugar and mix well.
Pour pecans on sheet tray and bake for 20 minutes. Remove from oven and let cool.
In a large bowl combine the mixed greens, candied pecans, guava slices, and add balsamic vinaigrette. Mix to combine. Season with salt and pepper if necessary.