• cherry tomatoes halved or heirloom tomatoes, sliced
• chopped red onion

• diced celery, optional

• 3 tablespoons Sherry vinegar, divided

• 3 tablespoons prepared horseradish
• 2 tablespoon Worcestershire sauce
• Juice of 1 lime
• 1 teaspoon hot pepper sauce
• 1/2 teaspoon celery salt
• 1/4 cup extra-virgin olive oil
• Kosher salt and freshly ground black pepper

Based loosely on http://www.epicurious.com/recipes/food/views/flank-steak-with-bl...