Mix Couscous Salad Dressing. In a small bowl or glass jar, combine 1/4 cup + 1 Tbsp. extra-virgin olive oil, 3 Tbsp. minced shallots, 2 Tbsp. champagne vinegar, 1 Tbsp. lemon juice, 2 tsp. honey, 1/4 tsp. kosher salt, and cracked black pepper to taste. Mix well to combine. Set aside to allow shallots to soften.
Prepare Couscous Salad. Heat 2 Tbsp. olive oil in a large skillet over medium. Add zucchini and sauté until it starts to develop some color, about 5 minutes. Cut the corn kernels off the cobs and add to the skillet. Cook 5 more minutes, stirring occasionally, until the corn and zucchini are nicely golden. Season with ~1/2 tsp. kosher salt and a few grinds of cracked black pepper. Transfer to a large mixing bowl.
Cook Couscous. In a medium saucepan, bring 1 cup water, 1 tsp. olive oil or butter, and 1/4 tsp. kosher salt to a boil over high heat. Turn off the heat, stir in the couscous, cover and let steam until all the liquid is absorbed, about 5 minutes.Fluff couscous with a fork, breaking up any clumps. Add to the bowl of sautéed zucchini and corn, and pour in half of shallot dressing; toss well to combine. (Dressing the couscous while it's warm helps it better absorb the flavors.)Wait to add remaining salad ingredients until the mixture slightly cools to prevent the herbs from wilting. Prepare Lemon Tarragon Butter. In a small bowl, combine softened butter, tarragon, grated garlic, and Aleppo pepper; mix well. Set aside ~1 Tbsp. of mixture to brush over the skewers after grilling.
Assemble Skewers. Thread shrimp and lemon slices on skewers, starting with one piece of shrimp and threading it so the skewer pierces through both the head and tail end. Follow with one slice of lemon, folded in half to create a crescent or into quarters to create more of a ruffled, accordion effect. Repeat, alternating the two, until you have 3 pieces of shrimp and 2 slices of lemon on each skewer (see in-process photos for reference). Sprinkle the skewers with ~1/2 tsp. kosher salt and cracked black pepper to taste.(Note: if desired, save the ends of the two lemons to grill and use as a garnish, as pictured above.) Grill Skewers. Set the grill or griddle to medium-high heat (about 400ºF) and brush the grates/surface carefully with oil (or heat a large grill pan on the stovetop over medium-high).Brush one side of the shrimp skewers with the tarragon butter mixture, and place the skewers (seasoned side down) directly on the grill grates (or griddle). Cook for ~3 minutes, until golden. Flip, and brush remaining side with tarragon butter. Cook for another 3 minutes. Remove to a plate, and brush reserved tarragon butter overtop. Sprinkle with flaky salt, if desired. Finish Couscous Salad. To the bowl of cooled couscous mixture, add diced peach, parsley, chives, and sunflower seeds. Pour in remaining dressing and toss well to combine. Taste and season with additional salt and/or black pepper, as needed.
Serve. There are two ways to serve the skewers and salad. Option 1 is emptying the couscous salad out onto a large serving platter and arranging the skewers overtop. Option 2 is keeping them separate, and spooning salad into individual plates or bowls, and topping with grilled shrimp and lemon slices (removed from skewer). The couscous salad is meant to be enjoyed at room temperature, and the shrimp warm.