Combine all ingredients in a bowl, cover and refrigerate until ready to use.
To make into a dip: combine all ingredients in a blender and whiz until smooth.
Trim the steaks of any connective tissue or fat and cut into 2-inch cubes. Add the seasoning, oil, then toss to coat.
Heat a cast iron skillet until almost smoking over medium-high heat and sear the steak bites in batches, about 2-3 minutes per side for medium and 3-4 for well done. Do not overcrowd the skillet, or the steak bites will boil instead of searing.
Transfer to a warm bowl, toss with as much or as little of chimichurri sauce and serve.