In a medium sauce pan place pecans and 1/4 sugar on med/low heat and cover
When sugar begins to melt, remove lid and stir continuously until pecans are lightly browned and evenly coated and the sugar is caramel in color being careful not to burn.
Transfer to a cutting board to cool
To make salad dressing whisk oil, vinegar, remaining sugar, pepper, salt, and dijon mustard until well incorporated.
Pile green into a large serving bowl, or on individual serving plates.
Thinly slice pears (and optional red onion) and sprinkle on tops of greens
Chop candied pecans and add to greens mixture along with feta cheese crumbles
Drizzle dressing over salad just before serving