Preheat the oven to 425°F. Toss the pumpkin cubes with olive oil, salt, and black pepper, then spread them in a single layer on a lined baking sheet. Roast for 20 to 25 minutes, turning once halfway through, until tender and lightly caramelized.
While the pumpkin is roasting, whisk together the olive oil, apple cider vinegar, maple syrup, Dijon mustard, salt, and black pepper in a small bowl. Taste and adjust the balance of sweetness and acidity if needed.
Add the mixed greens to a large serving bowl. Top with the roasted pumpkin, feta, pecans, dried cranberries, and sliced red onion.
Drizzle the maple Dijon dressing over the salad just before serving. Toss gently until everything is lightly coated, then serve while the pumpkin is slightly warm or at room temperature.