Rinse the rice and split peas. Add to a saucepan with 4 cups of water. Bring to the boil, reduce heat and simmer gently for 17 minutes or until just tender. Drain and rinse well under cold water. Spread out on a tray and refrigerate until required.
Pre-heat oven to 190°C (170°C fan-forced). Toss carrots and sweet potato in oil with spice mix. Season well and spread on an oven tray. Bake for 25 minutes until roasted.
Combine rice and split pea mix with walnuts, mint, oil and lemon juice. Season and toss well. Spread spinach leaves over a serving plate and top with rice mixture. Top with carrots and sweet potato.
Combine yoghurt and lemon rind, season well. Drizzle over salad with dollops of harissa, extra mint leaves and nuts.