Preheat the oven to 180°C fan.
Mix all the ingredients for the spice blend together and store in an airtight jar (you'll only need one tablespoon for this recipe, but the remainder can be kept for up to a month for use in marinades, chillies, or as a rub).
Using a sharp knife, cut the chicken breasts in half horizontally — you should have 4 chicken breast steaks. Coat the steaks with one tablespoon of the spice blend.
Place the chicken on a baking tray, then spray with low-calorie cooking spray. Place in the oven and roast for 15 minutes — until thoroughly cooked. Leave to cool while you prepare the dressing and salad.
Scoop the avocado flesh into a mini chopper or blender bowl. Add the coriander (stalks and all), yoghurt, lime juice, and coconut drink (or water). Blitz until you have a smooth dressing. If needed, add a little water to thin the mixture out. Then, give it a little taste and add the sweetener as you see fit. Season everything with salt and freshly ground pepper, to taste.
Place the lettuce, cucumber, onion, pepper, black beans, and sweetcorn into a large salad bowl. Toss together.
Slice the chicken and arrange on top. Drizzle over the dressing, then serve!