DRESSING: Put *1 tablespoon* of the lemon juice, little bit of cracked black pepper, and salt to taste into a non-reactive bowl; stir well. While whisking constantly, drizzle in olive oil to form a dressing; set aside.
TOPPING: Put goat cheese, remaining 2 tbsp. of lemon juice, finely ground black pepper and the flesh from the avocados into a bowl. Lightly mash with a fork; season with salt to taste.
Drizzle some olive oil on the baguettes then transfer baguettes to baking sheet and broil until just warmed through, 1–2 minutes.
Divide avocado mixture between the broiled baguette halves and spread to cover each. Top the baguette halves with tomato and cucumber slices, in any arrangement you wish. Drizzle some of the cracked pepper dressing onto each. Garnish with fresh herb of choice, a light sprinkle of coarse salt and if desired add a little bit of the green peppercorns in brine *or* capers.