In a large skillet on medium high heat add the olive oil and place bell peppers, onion and asparagus inside. Add 1 tablespoon fajita seasoning into the veggies. Sauté until almost tender. Remove from heat and set aside.
Pound the flank steak until 1/4 inch thick. Slice in half lengthwise and divide equally. Add the vegetables into the center and roll up and secure with a toothpick.
Heat the skillet to medium high heat. Season the steak roll ups with fajita seasoning. Add them into the skillet. Cook on each side for 2-3 minutes or until steak is cooked throughout.