Rinse the quinoa then add to a pot with 2 cups/500 ml water. Bring to a boil and stir frequently until all water is removed and quinoa is fluffy, about 15 minutes. While quinoa is cooking, wash and chop the peppers and cucumbers into small cubes. Chop walnuts, then add cooked quinoa, peppers and cucumbers into a large bowl. In a separate bowl combine olive oil, balsamic and salt, and stir. Mix in the dressing with the quinoa mixture until well combined. Note: you can serve right away but I prefer cooling in the fridge for at least 2 hours before serving.