Heat grill to medium. Place potatoes on microwavable plate. Pierce potatoes with fork several times. Microwave on high 5-6 minutes, or until fork-tender but still firm.
Let stand until cool enough to handle. In large bowl, toss potatoes, oil and 3 teaspoons seasoning until well coated.
Place potatoes on grill and cook, turning frequently, 4-5 minutes or until skin is crispy.
In large cast-iron skillet on grill, cook and stir bacon 8-10 minutes, or until crisp. Add yellow onion and bell pepper; cook and stir 2-3 minutes, or until tender-crisp.
Push bacon mixture to one side of skillet. Add potatoes to other side of skillet.
Smash each potato with heavy spatula, bottom of small sturdy bowl or meat pounder. Sprinkle potatoes with remaining seasoning.
Spoon bacon mixture over potatoes. Sprinkle with cheese. Cover pan or close grill. Cook 3-5 minutes, or until cheese is melted. To serve, sprinkle with green onions and dollops of sour cream.
Test kitchen tip: Cooking potatoes before grilling reduces overall grill time.