Roughly chop the lettuce, tomato, cucumber and red onion. Place in a bowl, drizzle with 2 teaspoons olive oil and season with salt and pepper. Toss to combine.
Heat remaining teaspoon of olive oil in a frying pan on medium. Cook the chopped burger patties until warmed through.
Toast or warm pita breads. Cut in half and spread with hummus. Fill with salad and chopped patties. Drizzle with tzatziki and sprinkle with fresh herbs, if using. Serve immediately.