For the spice mix, combine all the ingredients together in a medium non-metallic mixing bowl, stirring until well combined. Add olive oil and lime juice, stirring until mixture become a thin paste.
Add the chicken thighs, stirring until well coated. Cover bowl with plastic wrap and refrigerate for at least 2 hours, to allow chicken to marinate.
For corn salsa, heat a barbecue or chargrill pan to high.
Brush blanched sweetcorn with oil and place on preheated barbecue for 2-3 minutes on each side or until outside is charred. Remove from heat and allow to cool.
Using a sharp knife, remove the charred corn kernels from the cob and place in a small mixing bowl. Add the drained black beans, onion, tomatoes, coriander, jalapeno chilli, lime juice, salt and pepper, stirring to combine. Set aside until required.
To cook the chicken, heat a barbecue or chargrill pan to medium-high and thread marinated chicken onto 4 skewers. Place prepared chicken on preheated barbeque and cook for 3-4 minutes on each side or until cooked through.
To serve tacos, arrange tortillas, shredded lettuce, coriander sprigs, Greek yoghurt, crumbled feta, chargrilled sweetcorn salsa and cooked chicken on a serving platter.
To assemble tacos, place a little iceberg lettuce down the centre of each tortilla, followed by some coriander, salsa, sliced chicken, feta and a dollop of yoghurt.