How can I Remove .DS_Store files from a Git repository?

The best solution to tackle this issue is to Globally ignore these files from all the git repos on your system. This can be done by creating a global gitignore file like:

vi ~/.gitignore_global

Adding Rules for ignoring files like:

# Compiled source #
###################
*.com
*.class
*.dll
*.exe
*.o
*.so

# Packages #
############
# it's better to unpack these files and commit the raw source
# git has its own built in compression methods
*.7z
*.dmg
*.gz
*.iso
*.jar
*.rar
*.tar
*.zip

# Logs and databases #
######################
*.log
*.sql
*.sqlite

# OS generated files #
######################
.DS_Store
.DS_Store?
._*
.Spotlight-V100
.Trashes
ehthumbs.db
Thumbs.db

Now, add this file to your global git config:

git config --global core.excludesfile ~/.gitignore_global

Edit:

Removed Icons as they might need to be committed as application assets.