In a medium bowl, mix the chicken breast cubes, red onion, cilantro and feta.
In a small bowl, whisk the mayonnaise, Dijon mustard, lemon juice, minced garlic, kosher salt and black pepper.
Pour the dressing on the chicken salad and mix well to combine. Serve immediately, or chill for an hour to allow flavors to meld.
Video
Notes
*If you need to cook the chicken, use two (8 oz) raw chicken breasts. Spray them with oil, lightly sprinkle with salt and pepper, and bake in a 450°F oven until cooked through, about 20 minutes.