Hi Juan Miguel Callejas Romero,
It looks to me as though those two websites are identical. I would definitely settle on one of those domains and then set a 301 from the 'discontinued' domain to the new one.
If you have a market outside of spain, I'd probably advise you go with the .com. If I'm in the UK and see an .es domain I'm unlikely to click on it. Conversely, if you're exclusively in Spain and as a Spanish resident I see .es in a sea of .com's I'd likely click on that.
In summary: select the TLD which you think will have the best click-through rate (analytics may shine a light on this) and then 301 the other to that domain.
- Andrew