Preheat oven to 375°F. Place bacon on a slotted pan or wire rack inserted onto a rimmed baking sheet and bake to crisp and well-browned, 18 minutes. Cool and coarsely chop.
Combine yogurt, avocado, lemon juice, anchovies, garlic, herbs, scallions, chili pepper, vinegar, salt, pepper and EVOO in a high-power blender or food processor, and process the dressing to smooth.
In a small bowl, combine tomatoes and red onion.
To arrange salad, place lettuce leaves on a plate and top with dollops of dressing, tomatoes and red onion, chopped eggs, chicken, blue cheese and bacon bits. Pass extra dressing at table.