Federal judges must go through the formal impeachment process to be removed. This Constitutional process must be respected because: (1) it is the rule of law - our long established law, and (2) one person's "ridiculous" judge is another person's "wise and prudent" jurist and vice versa.
If I became POTUS, one of the very first things I would want to do in order to shrink the federal government would be to eliminate certain departments - Commerce, Energy, Education, Labor, HUD, and possibly others. Congress has passed legislation to fund these departments for decades, now, but since these departments are part of the Executive Branch, would I, as POTUS, be within my authority to unilaterally shut them down. I presume that I would have that authority, but I also understand that I would be in for the fight of my life against those (Democrats, for sure, but also a fair number of Republicans, as well) who would be loathe to suffer actual, physical shrinkage of the federal behemoth.
B.