Mix marinade ingredients (everything except chicken) in a small bowl. Add chicken and marinade in a large gallon size zip lock bag. Massage the marinade into the chicken to ensure its thoroughly coated. Leave it in the refrigerator to marinate for at least 24 hours.
Preheat grill to 500F and grill chicken until it is cooked all the way through and reaches an internal temperature of 165F. The chicken will stick to the grill if you flip to early so wait at least 5-10 minutes before flipping.
To make the salad: First prep and chop everything that needs to be prepped and chop (red peppers, onion, cilantro, cucumbers) adding to a large bowl as you go. Add in feta, raisins, almonds, tabbouleh, lemon juice and sumac. Toss and taste. Add salt, lemon juice, and pepper to taste.
Option to cut up chicken and toss it with the salad or serve it on top.
What I suggest is serving this salad with a bed of romaine lettuce on the bottom, topped with your tossed salad mixture. Otherwise, if you toss the romaine with the rest of the salad it will get soggy if you don’t serve it right away!
Garnish with additional feta, almond slivers, and cilantro.