To prepare stuffing, heat a large nonstick skillet over medium-high heat. Add salt and beef; cook 2 minutes, stirring to crumble. Stir in bell pepper and next 7 ingredients (through bay leaf); cook 5 minutes or until bell pepper is tender. Discard bay leaf.
To prepare plantains, working with one plantain at a time, cut a small portion from the outer curve to make a flat surface. Make a lengthwise cut on the inside curve, being careful not to cut all the way through (plantain will now resemble a canoe). Carefully scoop out about 1 tablespoon of plantain from center cut to allow room for filling. Repeat with remaining plantains. Place plantains on a baking sheet coated with cooking spray. Brush oil evenly over plantains. Sprinkle plantains with 1/4 teaspoon salt and red pepper.
Bake at 350° for 25 minutes or until plantains are tender; let cool slightly. Fill each plantain with 1/4 cup stuffing; top each with 1 tablespoon of cheese. Bake an additional 10 minutes or until plantains are tender and cheese melts.