Use your grill to make this quick, easy, and delicious meal. (No grill? Use a grill pan instead.)
Heat a grill to medium-high. Clean and lightly oil hot grill. Season steaks with salt and pepper; grill, 3 to 4 minutes per side for medium-rare, flipping once. Tent with foil on a cutting board. Let rest 10 minutes. Meanwhile, brush zucchini and red onion with olive oil; season with salt and pepper. Grill vegetables until crisp-tender, 2 to 3 minutes per side, flipping once. In a small bowl, combine mayonnaise and garlic.
Thinly slice steaks against the grain. Spread garlic mayonnaise on top halves of split rolls. Serve sliced steak on rolls with grilled vegetables, tomato slices, and arugula.