Is it possible to configure a site to site vpn tunnel using ikev2 between ASA firewall and IOS Router?
assuming both devices support ikev2.
Yes, IKEv2 is supported on both ASA and IOS with the correct version of code.
ASA is supported from version 8.4 or later, and IOS is supported on version 15.2(4)S or later.
Here is sample config on the ASA side:
And here is config guide on router side: