If you want to open the whole internal network for hosts located on the DMZ, you might as well place these DMZ hosts in your internal network. If, for some unknown reason, you would like to open up the gate, you need to setup static translations and an access-list entry. In your case you can use the real IP addresses for your inside hosts and setup an access-list that allows ip any any. The mask used in your static commands indicates the number of hosts. Assuming a internal network of 192.168.1.0/24, your config would look like this:
static (inside,dmz) 192.168.1.0 192.168.1.0 netmask 255.255.255.0
access-list 101 permit ip any 192.168.1.0 255.255.255.0
access-group 101 in interface dmz
You might want to reconsider your policy and limit traffic between the DMZ and internal network as much as possible. A compromise of an DMZ host should not result in a compromise of you whole network.