If you are having Achilles tendinitis and still want to get your walking in there is really only one shoe to help that I have found. This is the MBT shoe. (not sandals) The MBT rocker bottom shoe allows you to walk without stressing your Achilles tendon. This is important.. the Achilles tendon can injure easily so protecting it is important.
I have tried other "rocker bottom" shoes and they do not compare. I do NOT love MBT shoes. I feel like they are heavy and ugly but when my achilles is bothering me I use them. The MBT sandals do not help as much.. because they are not as confining as the shoes the sandals won't give your foot the same support.. the sandals do help but the shoes are the best way to go.
If you are new to MBT shoes you might need to start slowly.. a couple hours a day and work your way up. When your achilles is feeling better try alternating your MBTs with other shoes, I like Mizuno Wave Rider Running Shoes. Karhu Fulcrum shoes are kind of interesting.. they might work for you.. I find they are comfortable and alternate these in with my others. After wearing my MBTs all of these shoes make my feet feel light as a feather.