In a small bowl, whisk together the cumin, smoked paprika, turmeric, garlic powder, sea salt, and black pepper.
Slice the chicken breast into thin strips and toss with the spice blend until every piece is evenly coated.
Heat the olive oil in a large skillet over medium-high heat.
Add the chicken to the skillet and cook for 6 to 8 minutes, turning occasionally, until the pieces are golden brown and cooked through.
While the chicken is cooking, whisk together the Greek yogurt and lemon juice in a small bowl to create the sauce.
Place the warm cooked brown rice at the base of a serving bowl.
Arrange the spiced chicken, diced cucumber, and diced tomato over the rice.
Finish by drizzling the lemon-yogurt sauce over the entire bowl before serving.