Slice the chicken breast into thin, bite-sized strips and place them in a medium mixing bowl.
Add the ground cumin, coriander, turmeric, garlic powder, sea salt, and black pepper to the chicken, tossing until every piece is thoroughly coated in the spice blend.
Heat the extra virgin olive oil in a large skillet over medium-high heat.
Add the seasoned chicken to the skillet and sear for 6 to 8 minutes, stirring occasionally, until the edges are golden brown and the meat is cooked through.
While the chicken cooks, prepare the sauce by whisking together the Greek yogurt, tahini, and half of the lemon juice in a small bowl until smooth and creamy.
In a separate small bowl, combine the diced cucumber, halved cherry tomatoes, and minced red onion with the remaining lemon juice for a quick salad.
Assemble the bowl by layering the cooked basmati rice at the bottom and topping it with the warm shawarma chicken and the fresh vegetable salad.
Finish the dish by drizzling the yogurt tahini sauce over the top and serve immediately.