Hi @andymarksonline,
Yes, there is a way. Assign a different css class to your editor and set the background through it:
<RadzenHtmlEditor class="red-editor" />
<RadzenHtmlEditor class="green-editor" />
.red-editor .rz-html-editor-content {
background: red;
}
.green-editor .rz-html-editor-content {
background: green;
}