Preheat oven to 425°F. Melt spread in a medium skillet. Add onion and cook over medium heat in a skillet for 10 to 15 minutes or until soft and lightly browned.
While onions are cooking, place potatoes in a medium microwave-safe bowl and cover with plastic wrap. Make a small slit to vent, then microwave on high for 10 minutes or until potatoes are soft when gently squeezed. Let cool slightly, then cut in half and carefully scoop out potato leaving a 1/4-inch shell.
Mash potatoes, then stir in cooked onion, yogurt, hummus, roasted red bell peppers, smoked paprika, garlic salt and pepper.
Place potato skins on a baking sheet and fill with mashed potato mixture. Bake for 20 minutes or until tops are lightly browned. Top with slivered Kalamata olives, if desired.