Slice all peppers julienne style. You may want to remove seeds and white 'ribs' from the jalapeno, this is where it's heat comes from. Heat oil in saute pan on medium high. Don't let oil smoke! Add peppers, red pepper flake, and onion to heated oil. Cook about 5 minutes, stirring often. Add mushrooms and cook about 10 minutes longer or until all veggies start to brown. Season with salt and pepper if desired.