Drain the halloumi, place it on a cutting board and slice in wide thin pieces, about 8 slices. Pat the slices very dry with paper towels.

Heat the oil in a grill pan or a non-stick skillet over medium-high heat. Add the sliced halloumi in a single layer. Cook, undisturbed, until the bottoms are golden brown, 3 to 4 minutes.

Use a spatula to flip the halloumi and cook until the other side is also golden brown, 3 to 4 minutes longer. Transfer the halloumi to a plate; let cool for at least 5 minutes.

Plate the grilled halloumi with sliced tomatoes, sliced cucumbers, fresh mint, zaatar and a drizzle of olive oil, if desired. Enjoy on its own or with pita bread.