Preheat oven to 375 F degrees. Slice twelve 1/2-inch slices of bread from the baguette. Place on a baking sheet, and brush (or drizzle) generously with the olive oil. Sprinkle a little salt on each slice. Bake for about 10 minutes, or until crisp and slightly golden. Remove from oven and cool slightly.
Preheat the oven to broil on HI.
Assemble the crostini: baguette, mustard, pastrami, sauerkraut, and cheese. Place the crostini back on the baking sheet (lined with aluminum foil or parchment paper). Place in the middle oven rack and cook until cheese is melted, 5 minutes.
Arrange crostini on a serving platter. Serve a side of mustard. Garnish with black pepper and chopped parsley; serve.