If I'm right in thinking you want each color within it's own span, you need to join the values within the mapping. Each value of color
is an array containing the color's RGB values:
var color = colorThief.getPalette(sourceImage, 2);
var newHTML = $.map(color, function(value) {
return('<span>' + value.join(', ') + '</span>');
});
$("#results").html(newHTML.join(''));