Heat oven to 350°F. Unroll dough; separate into 4 rectangles. Firmly press perforations to seal. Sprinkle 2 tablespoons walnuts on each rectangle; press firmly into dough. Place on large nonstick cookie sheet. Bake 10 to 12 minutes or until golden brown. Cool slightly.
Meanwhile, in 12-inch skillet, cook bacon over medium-high heat 5 minutes or until crisp. Remove from skillet; drain on paper towels.
In large bowl, beat jam and vinegar with wire whisk until well blended. Add salad greens; toss to coat.
Place 2 flatbreads walnut sides up. Top each with bacon slices, salad greens and goat cheese. Top with remaining flatbreads, walnut sides down. Cut each sandwich in half.