Mix tequila, sesame oil, Dijon mustard, balsamic vinegar, garlic, salt, and pepper in a small bowl then place in a large zip-top bag with tri-tip. Marinate at least two hours before desired grilling time.
Grilling Method: Pre-heat gas grill to 400 degrees F. Place meat on grill top-side down for 4-5 minutes for nice grill marks. Flip over, reduce heat slightly and close lid,
To be prepared for flare-ups, keep an open beer by the grill and use as a 'fire extinguisher.' If no flare-ups occur, then enjoy the beer yourself!
Cook for 20-25 minutes or until meat thermometer inserted in center reads 135-140 degrees F. for medium. Slice thin and enjoy with the fire extinguisher beer or the liquid type of margarita of your choice.