No, Mage Hand can not be Opaque or Invisible.
Mage Hand (PHB, 256) does not allow for it to become Invisible. The language is clear in it's description of what it looks like:
A spectral, floating hand appears at a point you choose within range. The hand lasts for the duration or until you dismiss it as an action. The hand vanishes if it is ever more than 30 feet away from you or if you cast this spell again.
Using it to Blind
The language around how you can use your mage hand is also fairly clear(emphasis mine).
You can use your action to control the hand. You can use the hand to manipulate an object, open an unlocked door or container, stow or retrieve an item from an open container, or pour the contents out of a vial. You can move the hand up to 30 feet each time you use it.
The hand can't attack, activate magic items, or carry more than 10 pounds.
While using it to "blind" a creature isn't necessarily an attack, there also isn't an action that generally does this. Allowing a cantrip to easily give the Blinded condition would be significantly overpowered. If you aren't sure how that would play out, you could imagine that the hand tries to cover the eyes, and the creature simply moves their head. Without being able to 'hold' it over their eyes (which is basically an attack), then there is no way to keep it in front of them.
It is also spectral in form. That suggests that you can see through it as well even if it was over your eyes.
Mage Hand Legerdermain
You may be confusing Mage Hand with the Arcane Trickster's Mage Hand Legerdemain (PHB, 98)
Starting at 3rd level, when you cast mage hand, you can make the spectral hand invisible...
The spell Bigby's Hand (PHB 218) is a 5th level spell that doesn't even allow giving the Blinded condition. It can interpose itself between you and attacker giving 1/2 cover (and do a lot of other very cool things, including Grapple.)