Heat oil in a large skillet over medium-high heat; cook and stir onion in the hot oil until tender, 5 to 10 minutes. Remove onion from skillet to a bowl with a slotted spoon, leaving oil in skillet. Cook and stir steak in the same skillet over medium-high heat until browned and liquid has evaporated, 5 to 10 minutes.
Stir onion, jalapeno peppers, and pimento peppers into steak until thoroughly mixed. Add cream cheese to steak mixture; cook and stir until cream cheese is melted, about 5 minutes. Stir cheese sauce into steak mixture; cook and stir until dip is heated through, 3 to 5 minutes. Serve hot.
