To create the vinaigrette combine olive oil, lemon juice, dijon mustard, honey, minced shallot, fresh dill, salt, and black pepper.
Add spinach, smoked salmon, cucumber, slivered red onion, green onion, fresh dill, goat cheese, avocado, and vinaigrette to a large bowl and toss to combine. Garnish with fresh lemon slices.
Notes
If you plan on saving some of the smoked salmon salad for another day, I recommend storing it without the vinaigrette and avocado mixed in. To keep everything fresh I suggest adding them to each individual serving when you're ready to eat.
Lemon slices make a beautiful garnish, but sometimes I actually like to add bite-sized pieces to my salad. Not only does it add more variety to the textures of the salad, but the flavor of the lemon really enhances the taste of the salmon.