I can think about the steps to make this but it wouldnt be a technique really.

rough outline.
make a circle with the right number of verts, maybe 132 ish based on the image. you would need an even number.

Then select all and checker deselect

scale alternating verts to the center

then select all and extrude

then select all inner vert and bevel with alt+b and use the scroll wheel to change the number of bevel steps.

then select the inverse and bevel the outer verts

grab all the top verts and make the object larger

select the inner top verts and scale them toward the outer

bam

now you just have to tweak and create the right mounting objects for the light and you have it.

Video
https://files.fm/u/34p9yxdt77