1. In a small bowl, whisk together ingredients for dressing; set aside. Heat oven to 350 degrees F. Cut the baguette into eight 1/4-inch slices, spray with olive-oil, and bake until golden brown.
2. Crush the avocado with a fork, season with salt, and spread in a thin layer on each plate. Place 2 baguette slices on top. Dress the romaine leaves with the lemon-tarragon vinaigrette, season with salt and pepper, and arrange on plates. Garnish each plate with tomatoes, arugula, olives, fennel and tarragon.