Select only potatoes without any serious blemishes. Scrub the skins well with a brush or curly scrubber under cold running water.
Bake the potatoes till a little underdone--about 45 minutes.
After they cool, slice the potatoes from end to end in two. Scoop a little more than half the white part out of each potato half. Save what you scoop out for mashed potatoes.
Heat a tablespoon of the butter in a skillet over high heat. Sauté the shrimp, tasso, and green onions until the shrimp turn pink--just a couple of minutes at most.
Chop the shrimp and tasso mixture roughly, with a knife (don't use a food processor).
Turn on the broiler. Brush the insides of the potato tops and bottoms with butter. Broil the potatoes until you see a little browning around the edges.
Spoon into each potato skin about two tablespoons of the shrimp-and-tasso mixture. Top with enough shredded cheese to almost, but not quite cover. Return to the broiler until the cheese begins to bubble.
Mix the sauce ingredients. Serve the potato skins with the sauce on the side for dipping.