Slice the chicken breast into thin, bite-sized strips and place them in a medium mixing bowl.
In a small jar, whisk together the olive oil, half of the lemon juice, cumin, coriander, turmeric, garlic powder, sea salt, and black pepper to create the marinade.
Pour the spice marinade over the chicken strips, tossing well to ensure every piece is coated, and let it marinate for at least 10 minutes.
Heat a large non-stick skillet over medium-high heat and add the marinated chicken, cooking for 6 to 8 minutes until golden brown and fully cooked through.
While the chicken is cooking, dice the cucumber, halve the cherry tomatoes, and finely mince the red onion to prepare the fresh salad components.
In a small ramekin, stir the tahini with the remaining lemon juice and a teaspoon of warm water until it reaches a smooth, pourable consistency.
Place the cooked quinoa in the bottom of a serving bowl and top with the warm shawarma chicken and the prepared vegetable salad.
Drizzle the creamy tahini sauce over the entire bowl and serve immediately.