Question to "Start-up into resistive load" diagram of LTC3106
Your assumption is correct.   This chart describes the minimum resistance, using a 10uH Inductor, that will allow the converter to startup.  Otherwise it will not start or go into a protection mode.       

Many microcontroller and system on a chip semiconductor loads are not resistive in nature and only start to draw significant current after they reach a certain voltage and go through a startup sequence.  If your load is a microcontroller or processor then you can adjust this startup time to allow the converter to start.