Pat the chicken breasts dry with a paper towel. Season both sides with garlic powder, cumin, 1/4 teaspoon of salt, and 1/8 teaspoon of black pepper.
Heat 1 tablespoon of olive oil in a large skillet or grill pan over medium-high heat. Add the chicken and cook for 5-7 minutes per side, until golden brown and cooked through.
The chicken is done when an instant-read thermometer inserted into the thickest part registers 165°F (74°C).
Transfer the cooked chicken to a cutting board and let it rest for 5-10 minutes. Once rested, dice it into bite-sized pieces.
While the chicken cooks, combine the rinsed chickpeas, chopped cucumber, bell pepper, tomatoes, red onion, and parsley in a large salad bowl.
In a small bowl or a jar with a lid, combine the extra-virgin olive oil, lemon juice, red wine vinegar, minced garlic, the remaining 1/4 teaspoon of salt, 1/8 teaspoon of black pepper, and red pepper flakes, if using. Whisk or shake well to combine.
Pour the dressing over the vegetable and chickpea mixture. Toss gently to coat everything evenly.
Add the diced chicken to the bowl with the salad. Toss once more to combine.
Serve the salad immediately, or chill for 30 minutes to allow the flavors to meld.