Preheat the oven to 200 degrees C (180C fan-forced). Line a large baking tray with baking paper.
To make the minty mustard yoghurt, combine all the ingredients in a small jug. Add 1-2 tbs of water, just enough to reach a pouring consistency. Season well, then chill until required.
Combine the chickpeas and curry powder in a bowl, then spread over the prepared tray. Add the chicken to the tray and sprinkle with the orange zest, making sure that the chicken does not sit on top of the chickpeas. Bake for 20-25 minutes or until the chicken is cooked (turning the chicken once) and the chickpeas are golden crisp and starting to pop in the oven.
Divide the salad leaves, cucumber, tomato and orange slices evenly among shallow bowls. Top with the chicken, spiced chickpeas and extra mint.
Drizzle with the minty mustard yoghurt and serve warm.