To prepare the vegetables for the salad, core the tomatoes, cut in 6-8 wedges, then cut each wedge in half. Place the tomatoes into a large bowl, sprinkle with a pinch of sugar and toss. Add the sliced cucumbers, red onion and chopped basil and oregano and toss well.
To prepare the dressing, place the dressing ingredients into a small bowl and whisk together vigorously until well blended.
Pour the dressing over the vegetables and gently toss. Cover and set aside. You can prepare the salad several hours in advance and let it stand at room temperature to allow the flavors to blend.
To prepare the bread, lightly brush sourdough bread slices with olive oil or butter on both sides. Place on a foil-lined baking sheet 4-6 inches below the heating element and broil on high until lightly browned, about 2-3 minutes per side. Keep the oven door slightly ajar as you want the heating element to be on the entire time. Remove from the oven, let cool then break into bite size pieces and set aside.
Add the bread to the salad just before serving, give it a quick toss and serve. To keep the bread crispy longer, serve it sprinkled on top without tossing.