Combine 2 artichoke hearts, olive oil, and the next 6 ingredients (olive oil through garlic) in a blender or food processor, and process until mixture is smooth.
Chop the remaining artichoke hearts. Combine the chopped artichokes, pasta, spinach, and chopped tomato in a large bowl. Pour pureed artichoke mixture over pasta mixture, and toss well to coat. Cover and chill 2 hours. Sprinkle with feta cheese.