Season the chicken breast with dried oregano, sea salt, and black pepper on both sides.
Preheat a grill pan or outdoor grill to medium-high heat and lightly coat with a tiny bit of oil if needed.
Grill the chicken for 5-6 minutes per side or until the internal temperature reaches 165°F, then set aside to rest for 3 minutes before slicing.
While the chicken rests, place the halloumi slices on the grill for 1-2 minutes per side until charred grill marks appear and the cheese is softened.
In a small bowl, combine diced cucumber, halved cherry tomatoes, chopped parsley, lemon juice, and olive oil to create a quick salad.
Spread the hummus in a wide circle on a large plate or platter.
Arrange the sliced chicken, grilled halloumi, vegetable salad, and olives over the hummus base and serve immediately.