Clean, wash and pluck the salad into bite-sized pieces. Clean, wash and chop the peppers. Wash and halve the tomatoes. Wash and clean the cucumber and slice it lengthwise.
Peel onions and cut them into rings. Roast sunflower seeds in a pan without fat. Mix oil, vinegar and mustard. Season with salt, pepper and sugar. Mix the salad ingredients with the marinade.