1. Drain pineapple.
2. Into 12 x 8-inch microwave dish put in green pepper and onion.
3. Cover, microwave on HIGH 3 minutes.
4. In a mixing bowl, combine brown sugar and mustard and stir in beans and pineapple.
5. Put in to green pepper mixture and stir to combine.
6. Let it microwave, uncovered, on HIGH 8 to 10 minutes, stirring after 4 minutes.
7. Serve with Polish sausage or hot dogs if desired.