Pour ½ cup olive oil into a small bowl or liquid measuring cup. Prepare the following, adding each to the oil as you complete it: Finely grate the zest of 1 medium lemon. Juice the lemon until you have 2 tablespoons. Finely grate 1 garlic clove.

Add 2 tablespoons red wine vinegar, ¾ teaspoon kosher salt, and ½ teaspoon dried oregano. Whisk until combined.

Pat 1 pound skirt steak dry with paper towels. Place on a plate and season all over with ½ teaspoon of the kosher salt. Drizzle with ¼ cup of the dressing and flip to evenly coat with the dressing. Let sit at room temperature while the grill heats, at least 15 minutes.

Heat an outdoor grill for medium-high, direct heat (about 425ºF). Meanwhile, prepare the remaining salad ingredients.

Core and cut 2 medium romaine lettuce hearts into bite-sized pieces (about 9 cups). Place in a large bowl. Halve 1 cup grape tomatoes. Quarter ⅓ medium English cucumber lengthwise, then cut crosswise into ½-inch pieces (about 1 cup). Crumble 4 ounces feta cheese (about 1 cup). Crumble 1 cup pita chips.

Peel ½ large red onion, then quarter through the root end. Quarter 1 large bell pepper through the stem and remove the seeds and membranes. Place the onion and bell pepper on a baking sheet, drizzle with 1 tablespoon olive oil, and rub the oil evenly over the pieces. Season all over with the remaining ¼ teaspoon kosher salt.

When the grill is ready, scrape the grill grates clean if needed. Oil the grill grates with a paper towel dipped in olive oil. Grill the steak, onion, and pepper at the same time if it will fit in a single layer (otherwise grill the steak first): Place on the grill (reserve the baking sheet), cover, and grill until dark grill marks form on the bottom, 3 to 4 minutes. Flip everything over. Cover and grill until the steak is medium doneness (160°F as measured by a meat thermometer) and the onion and bell pepper are crisp-tender, 3 to 4 minutes more. Transfer each item to the reserved baking sheet as it is ready.

Drizzle ¼ cup of the remaining dressing onto the lettuce and toss to combine. Transfer to a large serving platter (about the size of a baking sheet) and arrange into an even layer. Cut the bell pepper into ½-inch thick strips. Cut the onion into rough 1-inch pieces and discard the stem end. Cut the steak crosswise into pieces about 3 inches long, then thinly slice each piece across the grain.

Arrange the following in rows on top of the lettuce, working from left to right: Bell pepper, cucumber, feta, steak in the middle, pita chips, onion, and tomatoes. Drizzle with the remaining dressing and sprinkle with a little more dried oregano if desired.