In a skillet over medium heat, stir 1/2 cup of sugar together with the pecans. Continue stirring gently until sugar has melted and caramelized the pecans. Then carefully transfer nuts onto waxed paper. Allow to cool, and break into pieces.
For the dressing, blend oil, vinegar, 1 1/2 teaspoons sugar, mustard, chopped garlic, salt, and pepper.
In a large serving bowl, first layer lettuce, pears, blue cheese, avocado, and green onions. Pour dressing over salad, sprinkle with pecans, and serve.