First make the dressing, by mixing the ingredients. Taste and adjust the sweetness, acidity and seasoning to your liking. Set aside.
Cook the couscous, following the instructions on the packets. Measure out the leftover rice or pearl barley. Put them in a mixing bowl.
Blanch the edamame beans in boiling water for 3 minutes. Add the spinach for the last minute of cooking. Rinse under cold water and add to the bowl.
Lightly toast the nuts and seeds (optional) and add to the salad.
Grate the carrot, add to the salad.
Add the red pepper and spring onion.
Add the dressing and toss well. Let it rest for at lest 15 minutes.
Just before serving, add the parsley and adjust the seasoning to your liking.