Place chopped veggies and sliced halloumi in a large bowl. Add olive oil, salt, and pepper to bowl and toss to coat.
In a small bowl whisk together tahini, water, balsamic vinegar, maple syrup, salt, and pepper. Set aside.
Heat grill or grill pan to medium-hot. Cook veggies and halloumi in batches, turning once until charred. Grill lemon halves on the grill and cook until you can see grill marks on the lemon.
While veggies and halloumi are cooking, brush bread slices with olive oil. Grill on both sides until grill marks are visible.
Arrange salad greens on a large platter, top with grilled veggies, halloumi, tahini dressing and fresh parsley. Season to taste. Squeeze grilled lemon over salad. Serve immediately with grilled bread.