1. Prepare the dressing by whisking together the olive oil and vinegar; set aside.
2. Cut the baguette in half lengthwise and spread both sides with pesto. Add a pinch of salt and sprinkle on half the crumbled blue cheese. Place under a hot broiler and toast.
3. Arrange the baguette halves on serving plates and layer with tomato slices and bacon. Toss greens with dressing and place on top. Sprinkle with remaining blue cheese.