Prepare the tofu feta about 4-8 hours before making the salad (I think it's easiest to prepare it the day before and allow it to marinate in the fridge overnight). In a small mixing bowl, whisk together the miso, lemon juice, and vinegar; you'll have a thick, smooth paste. Add the water and whisk till smooth, then whisk in the garlic, nutritional yeast, salt, pepper, and oregano. Place the cubed tofu in an airtight container (preferably one that's wide enough to allow tofu to rest in a single or double layer) and pour the marinade over the tofu. Shake to distribute the marinade over the tofu, then cover the container and transfer it to the fridge for at least 4-8 hours (preferably overnight).
In a large mixing bowl, combine the cooked barley, tomatoes, cucumber, mint, parsley, romaine, and olives or capers if using. Drain the tofu feta of its marinade and add the cubes. In a small mixing bowl, whisk together the olive oil, red wine vinegar, salt, and pepper. Pour this dressing over the salad ingredients, and toss gently, until everything is well combined. Serve with pita wedges, if desired.