In a large, deep saute pan bring 2 1/2-inches of water to a boil. When the water comes to a boil, lower the heat to a bare simmer. There should only be small, infrequent bubbles on the surface. Add 1/4 cup vinegar and some salt to the water. Crack 1 egg into a small bowl, making sure the yolk remains unbroken. Gently slip the egg into the simmering water, using a spoon to make sure the egg is completely covered. Repeat with the remaining eggs. Cook to desired degree of doneness, 3 to 5 minutes. When the eggs are done, remove from the water with a slotted spoon. Place on clean paper towels or kitchen towel to drain. Set aside.
In a small saute pan, cook the bacon until browned and crisp. Remove all but 2 tablespoons of the fat. Add the remaining 1/2 cup of white wine vinegar and stir, scraping up any browned bits on the bottom of the pan with a wooden spoon. Cook until the vinegar is reduced by half. Add the sugar and cook until it is dissolved. Season with salt and pepper.
Pour half of the bacon dressing over the frisee and toss with croutons. Divide the salad among 6 plates. Top each portion with a poached egg and a drizzle of the remaining dressing.