In a medium saucepan, combine the rinsed quinoa and chicken broth. Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes until the liquid is fully absorbed. Fluff with a fork and set aside.
In a large mixing bowl, whisk together the olive oil, lemon juice, oregano, garlic powder, salt, and pepper. Add the chicken cubes and toss until evenly coated.
Preheat a grill or grill pan to medium-high heat. Grill the chicken for 8 to 10 minutes, turning occasionally, until the internal temperature reaches 165°F (74°C).
In a separate bowl, toss together the diced cucumber, cherry tomatoes, and red onion to create the salad base.
Divide the cooked quinoa evenly across four meal prep containers or bowls.
Top the quinoa with equal portions of the grilled chicken and the cucumber-tomato salad.
Garnish each bowl with 1 tablespoon of crumbled feta cheese and 1 tablespoon of sliced olives.
Add a 2-tablespoon dollop of hummus to each bowl before serving or sealing for storage.