In a small bowl, whisk together the ground cumin, coriander, turmeric, garlic powder, sea salt, and black pepper to create the shawarma spice blend.
Coat the chicken breast evenly on all sides with the spice mixture.
Heat the extra virgin olive oil in a skillet over medium-high heat and sauté the chicken for 5 to 7 minutes per side until golden brown and cooked through.
While the chicken is cooking, prepare a quick salad by tossing the diced cucumber, tomato, and red onion with half of the lemon juice.
In a separate small dish, whisk the tahini with the remaining lemon juice and a teaspoon of water until the sauce is smooth and pourable.
Once the chicken is finished, remove it from the skillet and slice it into thin strips.
Assemble the bowl by placing the warm cooked brown rice at the bottom and topping it with the sliced chicken and the fresh vegetable salad.
Drizzle the creamy tahini sauce over the entire bowl and serve immediately.