I took a mini-quilt class once. The finished 4 patch and 9 patch blocks ended up 1 inch, so it was definitely some different technique. We used a tear away stabilizer to assemble the tiny pieces, and the seam allowances were a scant 1/8 inch. They suggested using a flannel instead of batting. One key thing is to find interesting fabrics that have designs or textures small enough to read well at such a tiny size.
To be honest, I found it pretty tedious piecing, and I never actually finished my mini. I do think they are intriguing though.