Gently pat shrimp dry with a paper towel and place them in a medium bowl. Spritz with cooking spray and add the onion powder, garlic powder, smoked paprika, 1/2 teaspoon salt, pepper and cayenne. Toss to evenly coat. Skewer shrimp onto pre-soaked wood or metal skewers. Set aside.
Spritz the bell pepper and zucchini. Season with 1/4 tsp salt and pepper.
Over medium-high heat, grill the bell pepper halves and zucchini for 4 minutes. Using long metal tongs, carefully turn the peppers and zucchini, then place the shrimp on the grill. Cook for an additional 4 minutes, flipping the shrimp after 2 minutes. Remove everything from the grill at the same time.
Microwave cauliflower rice for 4 minutes. Stir in cilantro, lime juice, salt and pepper. Divide over four servings.
Dice the peppers and zucchini and divide over cauliflower rice and top with shrimp, yogurt and garnish with fresh cilantro and lime wedges.