Preheat oven to 400 degrees. Mix together oil, paprika, salt and pepper. Stir the seasoning mix into the potatoes. Place potatoes evenly on a baking sheet. Roast for 30 minutes until golden and crispy.
While potatoes are season the steak with salt and pepper. Heat grill to high and grill steak 4-5 min minutes per side. For medium rare, grill steak until is reaches an internal temperature of 135°F.
Remove steak from grill and allow it to rest for a few minutes. Slice into thin strips about 1/2- 3/4 inch thick against the grain.
While steak rests, whisk the ingredients for the vinaigrette and set aside.
Divide salad greens between 4 plates. Top with sliced steak, tomatoes, onion, roasted potatoes, and blue cheese. Drizzle the vinaigrette over the top of the salad and serve.