Stir together the vegetable oil and the cornstarch in a bowl.
Add the black beans and stir it all up.
Pour the mixture into a quart sized ziploc baggie and add the tri-tip in.
Seal it up. Place this in your fridge for at least an hour to make sure the steak is well coated in the marinade.
After about an hour take out your tri-tip from the fridge and pour off any excess marinade and place the steak onto a hot grill and heat it up over the fire.
Slice up your peppers, onions, and tri-tip steak.
Once everything is sliced heat up some flour tortillas in a pan with a bit of vegetable or canola oil in it on high heat until you see them bubbling and turning brown.
Spoon in some of your black beans into the tortilla, followed by tri-tip slices and peppers and onions.
Fold it up and serve with a slice of lime and some orange juice, as well as salsa to taste.