In a saucepan, add a little olive oil and saute the onion, garlic, and jalapeno for a minute taking care not to burn the garlic.
Thinly slice the steak. Remember, this is an appetizer. You don't want to have big honkin pieces of meat on the skewer because it will make it more difficult to eat.
I'm using my grill pan but you can use your bbq grill. In fact, the bbq grill will give it some awesome smoky flavor. If you use the bbq grill, please make sure you soak the skewers well. You don't want them to burn to a crisp.