Heat oil over medium high heat in a large skillet. Cook ground beef and onions for five minutes, drain and return onion beef mixture to pan.
Lower heat to medium low. Add in seasonings and sofrito. Mix well.
Add in black beans, corn and cilantro. Allow to heat through, then turn off heat.
Serve beef mixture over desired lettuce types.
To make dressing, blend ingredients together until well blended. You can add avocado to the dressing to elevate creaminess if desired.