Wash spinach, pat dry, and place in a large bowl. Hull strawberries, halve if large. Slice avocados, remove seeds, and add to bowl. Chop almonds for later use.
Whisk balsamic vinegar, olive oil, honey, Dijon mustard, minced garlic, salt, and pepper in a small jug until emulsified. Adjust sweetness if needed.
Toss spinach with strawberries, avocado, and half the vinaigrette. Add crumbled feta and lemon zest, mixing until ingredients are dampened but not soggy.
Sprinkle chopped almonds over the top, and drizzle with remaining vinaigrette before serving.