BBQ halloumi fajita skewers

Name: BBQ halloumi fajita skewers
Ingredients: 3 peppers (any colour), cut into wedges; 2 large red onions cut into wedges; 2 x 250g blocks of halloumi halved then cut into quarters; 2 tbsp olive oil; 2 ripe avocados halved and stoned; 1 large lime juiced; 8 soft tortilla wraps; small bunch of coriander leaves picked; 120g soured cream; chipotle chilli sauce to serve (optional); 1 ½ tbsp smoked paprika; 2 tsp ground cumin; 2 tsp ground coriander; 2 tsp dried oregano; ½ tsp garlic powder; 4 metal skewers