Solar Irradiance is1400 W/m squared?

You don't give us enough information, but energy input = 1400 x 3600 J. (Actually the solar constant at the earth's surface is nearer 1 kW per sq m).

Mass = 100 kg.

So the temperature rise (not temperature) is 1400 x 3600 /(100 x sp ht cap of either sand or water)

You put in the figures and do the rest.

A different approach is to equate the power input (1400 W) with the power radiated (= Stefan's constant x emissivity x temperature^4)

It isn't clear what you are actually asking.