Whisk together all of the marinade ingredients. Trim the steak of fat. Score both sides of flank steak in a criss-cross. Put the steak in a deep dish or sealable plastic bag and pour in the marinade. Marinate the flank steak in the refrigerator for 6 to 8 hours before grilling.
Cook beans in cold water with 2 cloves of garlic. Add salt, about 10 minutes before the beans are done. They should be tender but not mushy.
Preheat the grill for 20 minutes. Bring the steak to room temperature.
Season the flank steak with salt and pepper. Grill 1 to 2 minutes each side. Allow to sit 15 minutes before slicing it. Arrange the arugula with the beans over top. Then place thinly sliced flank steak and corn relish over top. Garnish with the cilantro leaves.
Combine all ingredients in a preserving pan. Bring the mixture to a boil over medium heat, stirring occasionally. Simmer mixture for about 30 minutes until it has thickened slightly. Ladle boiling hot relish into hot, sterilized pint jars leaving 1/4-inch headspace. Seal the jars with new 2 piece lids then process for 15 minutes in a boiling bath. Cool and label jars. Allow to mellow for a couple of weeks before serving.
Recipe courtesy of Nancy Forrest, from In Good Taste