Would have to see a specific recipe to evaluate it. The few I have looked at not only call for added oil but call for cukes to replace most, if not all, the tomatoes. Calling it a salsa is really a misnomer.

Normal tomato-based salsa is so borderline safe as it is. And since cukes are much more alkaline, more low acid, than tomatoes the acidity of the remaining ingredients would determine the safety.

I honestly doubt it could be safely canned without a great deal of added vinegar and basically pickling it.

Dave

There's a recipe in the "Small Batch Canning" book. I made it last year and was unimpressed. I used it mostly to make guacamole.