You can control the number of major ticks with the majorTicks option, but there is no way to get rid of all of them. This option accepts an array of strings for the labels on the major tick marks *in between* the min and max values. The least you can have is 3, when you pass a single-element array to the majorTicks option.
You can, however, get rid of the minor tick marks, by setting the minorTicks option to 0. You can then use the majorTicks option to add as many tick marks to the Gauge as you want (pass empty strings for the array's values if you don't want them to have labels). This will give you a single style of tick marks for the whole Gauge.