Preheat the oven to 350F. To a baking sheet, add the bread, oil, salt and pepper and toss immediately to coat. Spread into an even layer and bake for 15 minutes or until the bread is crisp and firm but not browned or golden at all. Set aside to cool off.
To your largest mixing bowl, add the yogurt, oil, lemon, milk, mustard, pepper, and salt and whisk until smooth. Add the herbs, scallions, veggies, cucumber, and tomatoes.
Add the bread and use your hands to toss everything to coat. Let the salad sit for at least 15 minutes, tossing every few minutes. This will allow the bread to soak up the dressing and soften a bit.
Add most of the feta cheese and give it one last toss. Top with the remaining cheese, lots of black pepper, and a generous drizzle of your best olive oil.