Remove the sirloin steak from the refrigerator 20 minutes before cooking to bring it to room temperature, then pat it thoroughly dry with paper towels.
Season both sides of the steak generously with sea salt and cracked black pepper.
Heat the olive oil in a heavy cast-iron skillet over medium-high heat until the oil is shimmering but not smoking.
Place the steak in the skillet and sear for 3-4 minutes per side for medium-rare, or until your desired level of doneness is reached.
While the steak cooks, place the green beans in a steamer basket over boiling water, cover, and steam for 5-6 minutes until they are bright green and crisp-tender.
In a small dry pan over medium heat, toast the pumpkin seeds for 2-3 minutes, tossing frequently until they are fragrant and slightly golden.
Remove the steak from the pan and let it rest on a cutting board for at least 5 minutes to allow the juices to redistribute.
Slice the steak against the grain and serve alongside the steamed green beans, garnishing the entire plate with the toasted pumpkin seeds.