Rinse and dry the baby spinach thoroughly, then add it to a 12-inch / 30 cm salad bowl.
Hull the strawberries and slice them into thin pieces, about 5 mm thick.
Thinly slice the red onion into half moons, about 1/8 inch thick.
In a small jar, combine the mayonnaise, honey, apple cider vinegar, olive oil, poppy seeds, and a pinch of salt. Seal the lid and shake vigorously for 30 seconds until smooth and emulsified.
Add the sliced strawberries and red onion to the bowl with the spinach.
Scatter the crumbled feta and candied pecans over the top.
Drizzle the poppy seed dressing over the salad just before serving.
Toss gently with your hands or salad tongs until the leaves are lightly coated. Serve right away.