Prepare the Shrimp: In a medium bowl, combine the shrimp, baking soda, salt and sugar. Toss to coat. Thread the shrimp onto sets of 2 skewers, rotating heads to tails and threading the shrimp so they are snuggly pushed together. Each set of 2 skewers should fit about 6 shrimp. (Check out this link) Transfer the shrimp skewers on top of a baking dish so they are suspended above the bottom of the dish. Place, uncovered, in the refrigerator and allow the shrimp to rest for 45 minutes to 1 hour. Meanwhile, in a small bowl, combine 1 ½ tablespoons of oil with garlic, cumin and chili powder. In a separate bowl combine remaining 1 ½ tablespoons of oil with the lemon juice. Set both aside. Prepare the Couscous: Bring vegetable broth to a boil in a medium saucepan. Add the couscous, salt and butter. Cook until al dente, about 8-10 minutes. Stir in the squash. Set aside and allow to cool. Meanwhile, Prepare the Salad: In a large mixing bowl, combine the red bell pepper, red onion, scallions and garlic. Stir to combine. Add the cooled couscous & squash. Toss to combine. Set aside.Prepare the dressing: In a small mixing bowl, combine the olive oil, cumin, lemon juice, zest, white wine, honey and crushed red pepper flakes. Season with salt and pepper. Whisk well. Pour over the vegetables and couscous. Toss thoroughly to combine. Taste and adjust for seasoning. Set aside in the refrigerator.Grill the Shrimp & Corn: When hour is up, heat grill to high.For the Corn: Grill corn, turning occasionally, until charred and tender, about 10-15 minutes. Remove from heat to a clean work surface. Brush with butter and season with salt and pepper and set aside. When cool enough to handle, remove kernels from cob using a serrated knife. Add to the salad.For the Shrimp: Brush both sides of the shrimp with the garlic and oil mixture. Grill shrimp, turning occasionally, until cooked through (to internal temperature of 140 degrees – shrimp will continue to cook when you remove them) about 4-5 minutes. Transfer shrimp to a clean work surface and remove from skewers. Toss the shrimp in the oil and lemon mixture to coat. Season with salt and pepper to taste.Finish the Salad: Add the shrimp, avocado, fresh herbs, and parmesan to the salad. Toss to combine. Taste and adjust for seasoning. Serve with lemon wedges on the side.