1Prepare the dressing: Add cilantro, chives, garlic cloves, red wine vinegar, red pepper flakes, salt, pepper, and a squeeze of fresh lemon to a food processor. Pulse until broken down. Add olive oil and pulse until fully combined.
2Pat the steak dry and season generously with salt and pepper on both sides.
3Heat a skillet over medium-high heat. Once hot, add olive oil and sear the steak for 2-3 minutes on each side.
4Remove the steak from the skillet, top with 2 tbsp of dressing and let rest for 10 minutes before slicing against the grain into strips.
5In a large salad bowl or platter, layer the arugula, green onions, red onion slices, avocado, and blue cheese.
6Drizzle half of the remaining dressing and lightly toss to coat.
7Top with the sliced steak and drizzle with the remaining dressing.