Thank you for writing.
You can set RadColorBox value through the Value property for the initial state. For example in the OnLoad event of the form:
sender, EventArgs e)
.radColorBox1.Value = Color.Red;
Afterwards, as you have posted, you can track any changes through the ValueChanged/ing events.
I hope this will help. Should you have further questions, do not hesitate to write back.
the Telerik team