In a medium bowl, combine sliced red onion with red wine vinegar and a pinch of kosher salt. Let sit for at least 15 minutes.

In a small bowl, whisk together harissa, honey, and fresh lemon juice until smooth. Set aside.

Slice the halloumi cheese into 1/3-inch thick pieces and pat dry with a paper towel.

Heat olive oil in a skillet over medium-high heat. Cook halloumi for 1-2 minutes on each side until golden brown, then drizzle with glaze.

In a large bowl, combine pickled onions, diced cucumbers, cherry tomatoes, fresh dill, and grated garlic. Drizzle with olive oil and season with salt and pepper. Toss gently.

Warm pita bread until soft. Cut in half and spread tzatziki inside each pocket. Fill with glazed halloumi and salad.