a "choke cover" is the piece of metal that covers a carberator on a gas engine to help it start, then swings out of the way when it gets going.

I can't imagine how this term is used on a microwave. I'd like to see the parts list.

Looking around at various manuals (online) for microwave ovens, I determined that a "choke cover" is a part that covers the "choke seal" (a safety device) on a microwave oven.

I found this definition of a "choke seal" using Google:

tinyurl.com/9t6wu

"It's a small channel (gap) between the door perimeter and the opening that's tuned to the frequency of the microwaves and traps any that enter and basically lets them die off in there. Choke seals are nice because they don't require prefect contact between 2 pieces of metal (they can leak large amounts of air but block microwaves much better than an almost airtight metal-to-metal seal will) so aren't bothered by warpage or the door being pulled. Another seal is the capacitive type, which also shorts out the microwaves and also doesn't require perfect contact, and it's possible for doors have both types of seals. "

Not sure about the Spanish term for this. Your best bet is probably talking with a Spanish-speaking microwave repairman or technician.