Slice the chicken breast into thin strips for even cooking.
In a small bowl, combine the cumin, paprika, turmeric, coriander, salt, and pepper.
Toss the chicken strips in the spice blend until every piece is thoroughly coated.
Heat the olive oil in a large non-stick skillet over medium-high heat.
Add the chicken to the skillet and sauté for 6 to 8 minutes until golden brown and cooked through.
While the chicken is cooking, dice the cucumber and red onion, and halve the cherry tomatoes.
In a separate small bowl, whisk together the Greek yogurt, lemon juice, and dried oregano to create a zesty sauce.
Place the warm cooked brown rice in the base of a serving bowl.
Arrange the spiced chicken, cucumber, tomatoes, and onion over the rice.
Drizzle the yogurt sauce and tahini over the entire bowl and serve immediately.