Great for picnics because it's made with vinaigrette and therefore isn't as sensitive to the heat. Not a big seafood fan? Substitute grilled chicken for the shrimp if you like.
In a medium-size bowl, whisk together olive oil, vinegars, garlic, and oregano. Season with salt and pepper to taste and set dressing aside.
Preheat outdoor grill or indoor grill pan to medium. Brush both sides of halved leek with olive oil and grill until lightly charred and tender, about 5-7 minutes per side. Set aside to cool.
Season shrimp with salt and pepper and grill a few minutes on each side until cooked through; refrigerate until ready to serve.
When leek halves are cool enough to handle, cut into small pieces. In a large bowl, combine chopped leek, couscous, chickpeas, cucumber, tomatoes, olives, and artichokes; mix well. Toss in cubed feta and pour reserved dressing over mixture. Refrigerate several hours, or overnight if possible.
To serve, toss chilled couscous salad and top with chilled grilled shrimp.