I use bar soap to wash my hands in the bathroom, but I still like using liquid hand soap in the kitchen. I use liquid castile soap diluted with water in a foaming soap pump. You may be lucky to have liquid castile soap in bulk near you, or if you use a lot of it, you could buy the largest container available to cut down on packaging. There is one company I have found which sells castile soap in glass bottles. You can find it here.
If you aren't familiar with Plastic Free July, take a look at this post. Basically, it's a month-long challenge to reduce the amount of disposable plastic you use. It's a great starting point if you just want to give cutting out disposable plastic a try.
My first Plastic Free July was in 2013(!), and this month I'd like to highlight some of the things I do to reduce my plastic use, and some struggles. Many things are part of my routine at this point (buying in bulk, refusing plastic silverware, etc.), but I am not perfect, and I always find this challenge to be a good time to refocus and look at what trash I am actually producing.