Prep your vegetables by rinsing all peppers and onions thoroughly under cold water. Cut each bell pepper into 1½-inch chunks, removing seeds and white membranes completely. Slice red onions into 1½-inch pieces, keeping layers intact so they thread securely onto skewers.

Create your marinade by whisking together olive oil, balsamic vinegar, minced garlic, smoked paprika, dried oregano, kosher salt, black pepper, and cayenne pepper in a large mixing bowl. Whisk until fully combined and spices are evenly distributed throughout the oil and vinegar base.

Thread peppers and onions onto soaked wooden skewers alternating colors for visual appeal and even cooking. Start with a pepper chunk, then onion, then pepper again. Leave ½-inch space at the skewer tip. This pattern ensures charred grilled pepper skewers cook evenly across all surfaces.

Brush the prepared marinade generously over all threaded vegetables, rotating skewers to coat every side completely. Place skewers on a clean plate and let them rest for 5 minutes while your grill preheats to medium-high heat.

Place pepper skewers directly on the grill grates once flames reach 400°F temperature. Grill for 5-6 minutes on the first side without moving, allowing beautiful char marks to develop naturally. Turn skewers 90 degrees and grill for 4-5 minutes on the second side until peppers show deep caramelization.

Remove skewers from heat using tongs and transfer to a clean serving platter immediately. The residual heat continues cooking vegetables for 1-2 minutes after removal, so don't leave them on the grill too long.

Garnish hot pepper skewers with fresh chopped basil, fresh parsley, and crumbled feta cheese while vegetables are still steaming. Serve with fresh lemon wedges for guests who enjoy bright acidity alongside the smoky char.