The following keybindings will allow you to create multiple cursors (above or below the current cursor) with Command + Option + (Up|Down)
. On Windows it would be Control + Alt + (Up|Down)
.
{ "keys": ["super+alt+up"], "command": "select_lines", "args": {"forward": false} },
{ "keys": ["super+alt+down"], "command": "select_lines", "args": {"forward": true} }