Here's a post  by Robert Naiman that provides a useful list of the most Democratic congressional districts in which the incumbent has supported wars, and a list of districts where the incumbent showed some very minimal pretense of interest in peace but was defeated last month.
Naiman's analysis, in my opinion, needs tweaking, but is nonetheless a great place to start. It needs tweaking because, rather than looking at the list  of congressmembers who have voted against funding war or escalation, he looks at the list of those who have supported toothless deferential requests to the royal throne to consider ending the war in Afghanistan at any unspecified time in the future. This may give us the list of those who need the least pressure from the peace movement, or it may not. Moving some of these people from a position that defers to the president to one that asserts power may be harder than moving others from war support to real war opposition. In any case, neither the list Naiman uses nor the one I suggest as superior gives us a list of congress members who need no pressure at all. (The most recent funding vote involved no White House pressure for yes votes and no likelihood of defeat.) Our energy might be better spent firming up some of those who are closer to backing peace than trying to convert some of the militarists. But the existence of anything that might be called "our energy" is a wonderful thing in iteself, wherever it is to be found, and it cannot necessarily be moved around to suit our priorities, and it is not a finite substance.