Sprinkle za’atar seasoning over both sides of chicken tenders. Brush lightly with 1 tablespoon oil. Thread chicken onto 8 (6-inch) skewers. (If using wooden skewers, soak in water to prevent from burning while cooking.)
Broil or grill chicken for 7 minutes on each side or until no longer pink in center. While chicken is cooking, make mint harissa.
Place spinach, mint, jalapeño, garlic, lemon juice and bouillon in food processor; cover. Process for a few seconds. While processor is running, remove feed tube cover and pour in remaining 3 tablespoons oil.
Remove skewers from chicken. Serve with mint harissa.