Slice off about 1/4 of peppers lengthwise. Finely chop the slices; place in a large bowl. Remove and discard seeds from pepper "boats." Cook in simmering water to cover, 4 minutes or until crisp-tender. Drain well; transfer to a 13 x 9-inch glass baking dish.
Add rice, shrimp, salsa and seasoning mix to bowl with chopped peppers; mix well. Stir in 1 cup cheese. Spoon mixture into peppers boats, mounding if necessary.
Bake in a preheated 375°F oven 20 minutes or until hot. Combine cilantro and remaining cheese; sprinkle over pepper boats. Return to oven; bake 2 minutes or until cheese is melted.