How to pan fry zucchini without making it soggy

For pan frying you probably want to start with a firm tofu. It's a good idea to press the tofu to remove excess water: wrap the tofu in a cloth and place it between two cutting boards, weighting the top cutting board with a heavy book or other similar object. Wait at least twenty minutes (you can prepare the rest of the vegetables/onions for the stir fry at this point.

Once the tofu has been pressed, cut it into the desired pieces. It's a good idea to fry it at medium-high heat in only oil first, then add sauces (soy sauce, vinegar, whatever) only after the tofu begins to brown slightly.

Note: the above won't simulate deep-fried tofu. For deep fried tofu, you may want to use a softer tofu, still press it before using, and coat the cubes in corn starch before frying. Of course you probably know you can deep-fry at home with just a large pot of oil.

For a different texture you can freeze the tofu before frying.

Although not fried, I would also recommend that you try baked (marinaded) tofu to see if you like that texture/flavor better. You would still want to press the tofu, then slice it rather thinly. You can reapply the marinade during baking for more flavor.

I think your problem will disappear with proper technique. Zucchini and eggplant are indeed full of water. You have to both salt them well, to draw out the water, and cook them long enough for the liquid to evaporate.

It sounds like you are both under-salting and under-cooking. Try roasting for longer and/or at a higher temperature. My personal favorite way to do them is on the grill, where the direct heat and lack of a 'pan' allows lots of evaporation and also delicious browning.