While skillet is pre-heating, dice onions and pepper.
Add onions to heated pan and saute until caramelized, approx. 5-8 mins. Add peppers and cook until tender, approx. 3-5 mins. Add the garlic and let cook until fragrant.
Push vegetables to the side, and in the remaining area of the pan, cook the steak until heated through. Season with salt and pepper.
Remove to a bowl, tear beef apart and mix into the vegetables.
Evenly distribute filling across wrappers, fold, and place assembled egg rolls on a lined baking sheet. Spray lightly with cooking oil and bake 15-20 minutes until crispy.