Preheat your grill to medium-high heat. Season the steaks with salt and black pepper on both sides.
Brush the grill grates with olive oil to prevent sticking. Grill the steaks for about 4-5 minutes per side for medium-rare, or until your desired doneness is reached. Remove from the grill and let rest for 5 minutes before slicing.
While the steaks are resting, prepare the avocado dressing. In a blender or food processor, combine the avocado, Greek yogurt, lime juice, garlic, salt, and black pepper. Blend until smooth, adding water as needed to reach your desired consistency.
In a large bowl, combine the mixed greens, cherry tomatoes, red onion, diced avocado, feta cheese, and sliced almonds.
Slice the grilled steaks against the grain into thin strips. Add the steak to the salad and drizzle with the avocado dressing. Toss gently to combine.
Serve immediately and enjoy!