Place potato in a saucepan with enough cold water to cover. Bring to a boil, salt the water and cook until firm-tender, 3-4 minutes. Drain.
In a bowl, combine the shallot, garlic, lemon juice, lemon zest, vinegar, mustard, oregano and crushed red pepper. Whisk in about 1/3 cup EVOO to combine. Stir in the olives.
Preheat a grill pan or griddle over medium-high heat. Drizzle the meat (or whatever protein you are working with) with EVOO and rub all over; season with the rosemary, salt and pepper. Add to the pan and cook, turning once, for about 8 minutes for medium-rare. Let the meat rest for a few minutes, then slice on an angle,
Meanwhile, in a nonstick skillet, heat the remaining EVOO over medium-high heat. Add the potato cubes, season with salt and pepper. Cook until browned, 3-4 minutes. Flip the potatoes and add the onion and frying (or bell) pepper; cook for 5 minutes. Reserve the skillet.
In a large salad bowl, combine the romaine, tomatoes, parsley, feta and pepperoncini. Add the contents of the skillet to the bowl and combine.
Meanwhile, add the dressing to the skillet and heat for a minute. Pour over the salad and toss to coat. To serve, arrange the salad on plates and top with steak.