You want the technology report page, control+F7 (also visible under the empires dropdown menu).
This shows the basic details of all currently available systems, sorted by type, and obsolete systems are available with a checkbox in the corner.
You should be able to reverse engineer something by looking at the size, strength, power, and other details.
I realize this is exactly what JacenHan said earlier, but it's enough once you have some idea of the basic component strengths at different tech levels. The wiki really needs a list of what the different techs do to make reverse engineering easier, but most players just start a new game or have a test game and change the techs on the design screen around untill a system looks the same as the system they're trying to reverse engineer.

If you look at the missile design window, you should be able to call up past designs.

I believe in the system map there is a button somewhere along the top right which does what you are describing. It's name escapes me, but it's symbol is a circuit board if I remember correctly.