Preheat the oven to 400 degrees F. Set the baguette rounds on a parchment paper-lined baking sheet. Brush the tops of the bread with the 2 Tbsp. of the oil. Bake 8 to 10 minutes, or until lightly toasted. Combine remaining ingredients, except garnish, in a bowl. Place two slices of cheese on each toasted round. Divide and mound the shrimp mixture on the cheese. Bake for 5 minutes, or until the cheese is melted. Arrange on a serving tray, garnish each melt with a basil or oregano spring, and serve.
Note: To get bite-sized melts, use a baguette about 2" in diameter.