Hi,
You can try the ''sh cry ips sa summary'' command, it will give you an output similar to the one below:
ASA(config)# sh crypto ipsec sa summary
Current IPSec SA's: Peak IPSec SA's:
IPSec : 10 Peak Concurrent SA : 20
IPSec over UDP : 0 Peak Concurrent L2L : 20
IPSec over NAT-T : 0 Peak Concurrent RA : 0
IPSec over TCP : 0
IPSec VPN LB : 0
Total : 10
This shows the amount of connections, you can check the users with the ''sh cry ipse sa user ''
Federico.