Mix all the ingredients for the marinade in a large bowl and add the chicken thighs. Coat them well, cover the bowl and marinate in the fridge for anywhere between 2-24 hours.
Remove the chicken from the fridge 20 minutes before grilling and allow to come to room temperature.
Preheat the oven to 200℃, place a grilling rack over a sheet pan or a roasting pan. Place the chicken thighs on the rack making sure they're well spaced, and cook for 30 minutes, turning them over after 15 mins. Grill the chicken on the barbecue if you have one.
While the chicken is cooking, make the dressing by whisking the yoghurt with all the spice powders and salt. If it's too thick, use some of the drained whey to loosen it to a pouring consistency.
After 30 mins, raise the temperature of broiler (top coil of the oven) to 230℃ and cook the chicken for 5-7 mins till there are small char marks. Take the chicken thighs out, rest till they've cooled enough to handle and slice into large dices. They should be about the same size as the diced mango.
In a large salad bowl, add the chicken, jalapenos, cashewnuts, mango and chopped coriander. Add some of the yoghurt dressing and toss lightly to coat. Serve the salad with chilled iceberg wedges on the side, drizzled with the remaining dressing.