What is the best concealer for VERY dark undereye circles? I have dark tanned skin color but it always looks like I got punched in the face in the morning...

MAC has great products for it! If you don't want to spend the money that MAC costs I get my concealer from Perscriptives. I have the same problem as you and I love it. I also put it on my eye lids before I put my eyeshadows on to help them stay on longer