Cut Each Potato Lengthwise Into Four Wedges. Cut Away The White Portion, Leaving 1/4 In. On The Potato Skins. Place Skins On A Microwave-Safe Plate. Microwave, Uncovered, On High For 8-10 Minutes Or Until Tender. Brush Butter Over Shells; Top With Picante Sauce, Cheese And Bacon Bits. Grill Potatoes, Skin Side Down, Uncovered, Over Medium Heat For 4-6 Minutes Or Until Lightly Browned. Cover And Grill 2-3 Minutes Longer Or Until Cheese Is Melted. Sprinkle With Tomato And Onion. In A Small Bowl, Combine Topping Ingredients. Serve With Potato Skins.