Finely mince the shallot and add to a medium mixing bowl.
Add the Dijon mustard, whole grain mustard, white wine vinegar, and Manuka honey. Whisk to combine.
Let sit for 5–10 minutes to mellow the shallot.
Slowly drizzle in the olive oil and avocado oil while whisking continuously until emulsified.
Season with salt and pepper to taste.
Wash and dry the greens. Place in a large salad bowl.
Toast sunflower seeds in a dry skillet over medium heat until golden, 2–3 minutes. Set aside.
Drizzle 2–3 tablespoons of vinaigrette over greens and toss gently.
Top with marinated feta, toasted sunflower seeds, avocado slices, and fried dill if using.
Serve immediately.