Season the prawns with the spices, garlic and salt. Place a pan over a high heat and drizzle with olive oil. Sear the prawns on both sides until pink. Add the butter and toss to coat. Set aside.
Make the dressing by whisking the ingredients together. Marinate the fennel in the dressing for 15 minutes.
To make the salad, arrange the watercress and rocket on a large serving platter, top with the fennel, naartjies, avocado and dressing, and sprinkle with the chopped almonds.
Serve with the prawns.
Notes
NB: You will get a similar finish from using mandarines, tangerines or oranges.