Prepare the vegetables:
Wash and cut the zucchini, bell peppers, onion, and mushroom into 2.5cm (1 inch) chunks.
Prepare the marinades:
In one bowl, whisk together the olive oil, lemon juice, orange juice, parsley, cilantro, garlic, salt, and pepper for the citrus-herb marinade.
In another bowl, whisk together the yoghurt, tahini, lemon juice, water, garlic, salt, cumin, and black pepper for the tahini-yogurt dressing.
Marinate the vegetables:
Divide the vegetables evenly between two large resealable bags.
Pour half of the citrus-herb marinade into one bag and half of the tahini-yoghurt dressing into the other bag.
Toss the vegetables to coat them evenly.
Marinate in the refrigerator for at least 30 minutes or up to 2 hours.
Preheat the grill:
Preheat your grill to medium-high heat.
Assemble the skewers:
Thread the marinated vegetables onto skewers, alternating between colours and types of vegetables.
Grill the skewers:
Grill the skewers for 8-10 minutes, turning occasionally, until the vegetables are tender and slightly charred.
Serve and enjoy:
Serve the grilled vegetable skewers with a drizzle of the remaining marinades or dressings.
Enjoy the symphony of flavours!