Preheat oven to 350 degrees F. Toss bread cubes with olive oil, salt and pepper and place on a baking sheet. Bake until croutons are golden and crisp, about 8 minutes. Remove from oven, and allow to cool completely.
Make bacon bits:
Spray a nonstick pan with cooking spray and heat over medium-high heat. Add bacon and cook until crisp, stirring frequently, about 4 to 5 minutes. Allow to cool.
Combine the yogurt, mayonnaise, ketchup, vinegar and pickles in a bowl and stir to incorporate. Season with salt, to taste.
Toss the lettuce, tomato, onion, and cucumber in a large salad bowl with the dressing. Top with croutons, bacon bits, sliced chicken and serve.