Prep the skewers: If using wooden skewers, soak them in water for at least 30 minutes so they don’t burn on the grill.
Make the marinade: In a large bowl, whisk olive oil, soy sauce, Worcestershire, vinegar, honey, garlic, smoked paprika, black pepper, salt, oregano, and red pepper flakes.
Cut the steak: Trim excess fat and cut steak into even 1.5-inch cubes. Add to the marinade and toss to coat.
Marinate for at least 30 minutes and up to 8 hours in the fridge.
Prep the veggies: Cut peppers and onion into similar-sized pieces. Pat tomatoes and zucchini dry. Drizzle with a little olive oil and a pinch of salt and pepper.
Assemble the kabobs: Thread steak and veggies onto skewers, alternating pieces.
Don’t pack them too tightly—leave small gaps so heat can circulate.
Preheat the grill: Heat a gas or charcoal grill to medium-high (about 425–450°F). Clean and oil the grates to prevent sticking.
Grill the kabobs: Place skewers on the grill. Cook 10–12 minutes total, turning every 2–3 minutes, until the steak is 130–135°F for medium-rare or to your preferred doneness.
Finish and rest: Transfer to a platter.
Squeeze fresh lemon over the top, sprinkle with parsley, and let rest 5 minutes so the juices settle.
Serve: Taste and add a pinch more salt if needed. Serve with rice, grilled flatbread, or a crisp salad.