Three Greens and Fruit with Vinaigrette Recipe

6 tablespoons white wine vinegar

6 tablespoons vegetable oil

1 red onion

thinly sliced

¼ cup white sugar

¼ teaspoon salt

2 dashes hot pepper sauce

¾ teaspoon ground black pepper to taste

½ cup coarsely chopped walnuts

1 head romaine lettuce

torn

1 head butter lettuce

torn

2 bunches fresh spinach leaves

2 pears

cored and sliced

1 (4 ounce) package feta cheese