<div id="surface"></div>
<script>
var draw = kendo.drawing;
var geom = kendo.geometry;
var surface = draw.Surface.create($("#surface"));

var rect = new draw.Rect(new geom.Rect([10, 10], [100, 50]), {
    fill: {
        color: "#0066cc",
        opacity: 0.5  // 50% transparency
    }
});

surface.draw(rect);
</script>