Preheat grill to medium heat.
Brush London broil with olive oil and season with steak seasoning. Place on grill. Grill 3 to 5 minutes per side, depending on thickness and preference. When done, let rest 5 minutes then slice on the bias.
In a small bowl, combine pesto and mayonnaise.
Spread mayonnaise blend on bottom half of each ciabatta. Top with tomato slices and meat. Cover with the top halves and serve.
Recipe courtesy of Sandra Lee, 2007