I was playing a game against my friends and I got really hot dice that rolled crits a lot. (My prox bomb even rolled two crits and a hit)

The wording of the card of sensor jammer makes it seem like it can't roll crits. Which made my friend pretty frustrated for spending so many points on a card that didn't trigger that much.

Did we play that right or can the jammer jam crits as well?

The defending ship with the Sensor Jammer can change 1 of the attackers hits, so if you're rolling a lot of crits, that's just unfortunate for him. It is expensive, but considering there are more hits on the dice than crits, it would normally be more effective. Lady Luck can be a fickle cow sometimes.

When it comes to rolling dice [kaboom] results are not the same as [boom] results. If something will work with both it will say so and both are looked at when it comes to scoring an actual hit on a ship but beyond that the two are different things.

This is another case where things get confused because two different types of die results can result in a "hit" ship but those die results are still different from each other and calling them [crits] and [hits] can confuse the issue.