When we make this recipe, we start with 1/2 – 3/4 teaspoon pepper and 1/4 cup red onion and add more from there as desired. If you are eating this salad immediately, you can probably err on the side of more pepper and onion rather than less. If you will be letting it sit for an afternoon, or even a day or two, then I would suggest starting with smaller amounts of pepper and onion. As the salad sits, the flavor will intensify. And, if you are making this for a get-together, I would suggest preparing your ingredients separately ahead of time and then adding everything together just before serving.