Thinly slice the red onion. Place in a shallow bowl and cover the slices with cold water. Let soak for 10 minutes and then drain.
In a dry skillet over medium-low heat, add in chopped nuts. Toast for 3-4 minutes, tossing regularly. Remove from skillet and let cool.
Arrange the greens in a large serving dish.
Toss the greens with ¼ cup of prepared salad dressing.
Scatter orange segments, red onions, and pomegranate seeds on top of greens. Sprinkle with feta cheese and nuts. Serve with the remaining dressing on the side.
For the Dressing
Whisk together the vinegar, olive oil, mustard, honey, and salt together.
Using a mircoplane grater, grate the garlic into the dressing. Whisk well.
Notes
I prefer a mix of arugula and baby spring greens for this salad, but spinach works.
Soaking the onion is not necessary, but does help to mellow out the sharpness of the onion. Feel free to use shallots in place of the red onion.
In place of the feta cheese, crumbled goat cheese is a good substitute. Or omit the cheese altogether for a vegan friendly side salad.
If you do not have champagne vinegar, use white wine vinegar, balsamic vinegar, or apple cider vinegar.
Use maple syrup in place of honey in salad dressing to keep this dressing vegan friendly.