If using wooden skewers, soak them in water for at least 20 minutes to prevent them from burning on the grill.
In a medium-sized bowl, whisk together the extra virgin olive oil, minced garlic, lemon juice, lemon zest, red pepper flakes, sea salt, and black pepper.
Add the prawns to the marinade and toss until thoroughly coated; set aside in the refrigerator for 10-15 minutes.
While the prawns marinate, cut the red bell pepper and red onion into 1-inch chunks, and slice the zucchini into half-inch rounds.
Thread the marinated prawns and vegetable pieces onto the skewers, alternating between the protein and the different vegetables for even cooking.
Preheat a grill or a cast-iron grill pan over medium-high heat and lightly grease the surface with a small amount of oil if needed.
Place the skewers on the grill and cook for 3-4 minutes per side, until the prawns are pink and opaque and the vegetables have developed charred edges.
Remove from the heat and serve immediately while hot, perhaps with an extra squeeze of fresh lemon juice.