Make the dressing: combine both types of maple syrup and the olive oil in the bowl. Add the cider vinegar, then whisk in the mustard. Add the sage, salt and pepper to taste. Stir again, and set the dressing aside.
Place the salad greens in a large salad bowl. Add the cabbage.
Add the bell pepper to the salad, followed by the feta.
Add 3 tablespoons of the dressing all around the salad, then use salad tongs to toss well, and have the dressing thoroughly distributed and coating all the greens. You can add a bit more of the dressing if needed, or offer it at the table for people to take more for themselves.
Plate the salad, and top each serving with a sprinkling of the pumpkin seeds.