Using a sharp knife, score fat side of pork belly by slicing diagonally about 1 1/2-inches apart. Do not penetrate meat.
Combine spice rub ingredients. Season all sides of pork bellies with 1/2 cup rub; pressing deep into score marks. Store remaining rub for additional uses. Place pork bellies, fat side up, in shallow roasting pan; cover and refrigerate 24 hours.
To make mustard, combine jam, mustards, agave nectar and wasabi powder; mix well. Cover and refrigerate.
Heat convection oven to 275°F. Remove cover from bellies and roast 1 hour; remove from oven. Pour apple and pineapple juice over bellies; cover tightly with aluminum foil. Braise about 1 1/2 hours or until very tender. Let rest 30 minutes and slice thin.
On heel of pretzel roll layer 2 oz. pork belly, 2 teaspoons raspberry wasabi mustard, 1 oz. rosemary goat cheese and crown of roll. Serve immediately. Makes 30 sliders.