Garnish with reserved shrimp. Sprinkle with additional cayenne pepper for color if desired. Makes 2 servings. Stir oil, tarragon and garlic in small saucepan over low heat until fragrant, about 2 minutes. Season to taste with salt and pepper.
Arrange bread slices on small baking sheet.
Broil until golden, about 1 minute. Turn toasts over. Brush with oil mixture, dividing equally. Broil toasts until golden and crisp, about 1 minute. Serve toasts warm.