Add all prepped salad ingredients to a medium sized serving bowl.
Make dressing: whisk vinegar, Dijon, garlic, pepper, and salt together in a 1 cup glass measure (for easy pouring) or a small bowl. Add the olive oil and whisk until everything is combined well.
Pour dressing over salad ingredients and toss well until everything is coated.
Serve immediately or refrigerate for a day or two.*
Notes
*Optional for longer storage: leave out the nuts and add them in before serving so they don't go soft (I think they're fine even at day 4, which is why it's optional - do what you like).