Hello Pcaltagirone22,
you can use L3 load balancing using each link as a distinct routed interface.
Depending on configuration and effective support of L2 protocol tunneling you may be able to use the pair of links as an etherchannel.
In that case I would use LACP if possible. This can be supported or not depending on how the metro ethernet service is implemented.
First approach works in any case, second case allows to extend some vlans over the two sites that can be useful.
You need to check with your service provider if second option is available to you.
If there is no need for vlan extension I would go for L3 load balancing
Hope to help
Giuseppe