In a shallow dish, whisk together the yogurt, olive oil, garlic, kosher salt, black pepper, paprika, cumin and cayenne.
Add the chicken, turning it to make sure it's well-coated.
Set aside to marinate for 30 minutes, or cover, place in the fridge and marinate for a few hours.
Heat grill, dual-contact grill or grill pan on high heat, about 5 minutes. Spray the grill with olive oil spray. Grill the chicken breasts 4-6 minutes on each side, or for a total of 4-6 minutes on dual contact grill, until juicily cooked through and an instant-read thermometer registers 165 degrees F.
Rest the chicken 5-10 minutes before slicing and serving.