Mix lemon juice with the rest of the marinade ingredients until well blended. Pour marinade on steak in a marinating pan, let sit for at least 1 hour, flipping half way through.
Heat the grill to high. Add steak after the grill has reached operating temperature. It should take 4-5 minutes per side for a medium-rare steak. Place on a cutting board, cover with foil to rest for 5-8 minutes before slicing.
Dressing
Mix the olive oil, dijon mustard and balsamic vinegar until well blended. Add the shallots and basil, mix thoroughly.
Salad
In a large glass bowl, toss the arugula, tomatoes and avocado. Slice and add the steak (be sure to slice the steak across the grain).
Pour dressing over the salad and mix well. Garnish with crumbled goat or blue cheese. Season with sea salt and freshly cracked pepper if desired before serving.