Preheat your oven to 200°C (400°F). In a large bowl, whisk together the olive oil, cumin, smoked paprika, salt, and black pepper. Add the chicken breast and mix until coated. The mixture should have a vibrant, aromatic smell and a smooth, even texture.

While the chicken is cooking, heat a large frying pan or skillet over medium-high heat. Add the diced onion and cook for 5-7 minutes, or until softened and translucent. The onion should be caramelized and fragrant, with a deep golden brown colour and a sweet, slightly crunchy texture.

Add the minced garlic to the pan and cook for an additional 1-2 minutes, or until fragrant. The garlic should be soft and creamy, with a pungent aroma and a smooth, velvety texture.

Warm the pita breads by wrapping them in foil and heating them in the oven for 2-3 minutes. The pita breads should be soft and pliable, with a warm, slightly crispy texture and a gentle aroma of toasted bread.

Assemble the shawarma bowls by slicing the cooked chicken and placing it on top of the pita bread, along with the cooked onion and garlic, tahini sauce, chopped cucumber, tomato, and parsley. The finished dish should be a vibrant, colourful mix of textures and flavours, with a satisfying crunch and a refreshing, tangy taste.