Drain excess liquid off beans. Heat over medium low heat with a touch of butter. Cook until slightly softened. Add 2 to 3 tablespoons of vinaigrette, salt and pepper to taste. Pulse in food processor or mash in pot with a hand masher.
Slice bread, remove crust (if necessary), brush with olive oil. Sprinkle with salt and pepper and bake at 275 degrees until toasted or under broiler on both sides.
Spread 1 to 2 tablespoons bean tapenade and garnish with scallions.