Place 1 tablespoon oil, seasoning and chicken in a medium bowl, tossing well to coat chicken.
Heat a barbecue chargrill or hotplate over medium-high heat. Add chicken and cook for 3 minutes each side or until cooked through. Transfer to a plate. Add rolls, cut-side down, and cook for 2 minutes or until toasted.
Meanwhile, place cabbage, rocket, lemon juice and remaining oil in a large bowl. Season with freshly ground black pepper, tossing to combine.
Spread roll bases with hummus. Top with half the salad and cucumber, then chicken. Crumble over feta, then sandwich with roll tops. Add capsicum and remaining cucumber to rocket salad, tossing to combine. Serve burgers with remaining salad.