Combine oil, vinegar, maple syrup, mustard, honey, paprika, salt, and pepper in a lidded glass jar. Process with an immersion blender until well combined, about 30 seconds, or seal with lid, and shake vigorously. Make the Salad:
Heat a small skillet over medium-high. Add almonds; cook, stirring often, until toasted and golden brown, 1 to 2 minutes. Remove from heat; transfer almonds to a plate, and set aside.
Toss together spinach, apple, blueberries, feta, and toasted almonds in a large heatproof bowl. Set aside.
Add dressing to skillet; heat over medium until it just begins to simmer, about 1 minute. Pour about 6 tablespoons warm dressing over salad, and toss to coat. Season with salt and pepper to taste. Serve salad with remaining warm dressing, if desired.
