I don't know if Salandria criticized Garrison, but he was aware that his investigation was skewed at least. Litwin describes one instance where (over the objections of his staff) Garrison wanted to charge Robert Perrin (who was dead), Edgar Eugene Bradley and the three tramps in the assassination. Salandria and Weisberg went to New Orleans and talked Garrison out of it by convincing him that Boxley (who had hatched the scheme) was a CIA plant. Sciambra promised Weisberg "the best Italian dinner" as a reward.
Tom Bethell, who worked for Garrison before quitting in disgust over the entire farce, recounted an episode where Salandria was introduced to the Garrison staff for a sort of "pep talk" (my words not his). Here's Bethell's account:
"Salandria started off by telling us that we were in much better shape now than on the occasion of his earlier visit, in July. I had accompanied him around at that time, and I recall he was shown the Shaw file. He looked through it, and was rather rueful about it to me. He admitted to me that there wasn't much there. Now, however, it was a different story, or so he seemed to think. He could tell by the expressions on our faces. The case against Shaw was now looking much more solid, he told us, and we were beginning to work as a team.
He then started to urge us that the only trouble was we weren't going far enough, and he then started to work himself up into a harangue about Michael and Ruth Paine. "They're agents," he said, "I know they're agents. I've got the proof." He went on at some length about how he had met the Paines, and he produced some quasi-evidence suggesting they were agents etc. Then he told us to go ahead and charge the Paines -- "You've got all the evidence you need." He exhorted us to charge some others too, Marina Oswald, and Allan Dulles. Don't worry about anything, just go ahead and charge them, "the evidence is THERE!"
Garrison sat next to Salandria through all this, calmly smoking his pipe. Salandria was getting really worked up by this time, and was actually shouting at us. Someone asked him to tell us some of the evidence, and then he pulled out a few card indexes -- seemingly a little annoyed at being distracted by such trivia -- and then started off on his stuff about troop increases in Vietnam, the radio message to Airforce One, the same stuff he had shown me earlier on when he was working on the manuscript on WHY Kennedy was killed with his friend Tom Katen.
When he finished he was fairly attacked by several members of the staff, notably Jim Alcock and Charlie Ward....."
The rest here:
http://mcadams.posc.mu.edu/bethell4.htmI'd suggest that's not the words of someone who was critical of Garrison in this farce <g>. But maybe he had second thoughts.