Combine olive oil, scallions, mint, parsley, basil, garlic, anchovy, lime juice and salt. In a bowl mix shrimp with ½ cup of herb sauce. Chill and marinate for 1 hr. Reserve the remaining sauce.
Prepare couscous according to package directions. Heat grill to medium high. Cut zucchini into ¼-inch-thick strips and brush with some of the reserved herb sauce. Grill zucchini until just tender, 7 to 8 min, then dice and add to couscous.
Grill shrimp until just opaque and done, about 5 min. Add shrimp, feta and reserved sauce to couscous and toss together. Sprinkle with red pepper flakes and serve.
It’s recommended that you cook couscous by adding it to previously boiled water rather than sticking it in a pot of water and bringing it to a boil. Once you add in the couscous, take the pot off of the heat completely to make sure you don’t overcook it.