1. Whisk together first 5 ingredients (through pepper) in a small bowl until smooth. Add the vinegar, 2 tablespoons water, and olive oil, whisking until well-combined.
2. Combine the spinach, cranberries, and pumpkinseeds in a large bowl. Add the vinaigrette, and toss until well-coated. Divide the salad evenly among 4 plates. Arrange the Manchego slices evenly over each salad; serve immediately.