After the opponent hits the wall, several things are viable. You can do the aformentioned wall splatting attacks, and 4K after them twice for just a weird regular combo. Any combination of 3AB BE and EWGF is usually accepted, and some videos will show you better than words how strong those are... Finally, 66B also wall splats, but the range and obviousness makes it normally useless.
Now wall combos, the easiest way, again, is punishing with EWGF near the wall. Of course, that may not always be viable, so the other easiest way would be counter hitting with 4K and 26 AA3B. Surprisingly, CH 66KAK will counter hitstun and knock into the wall at certain angles. Wonderfully, 66KAK is a mixup with its 2K variant, and because most people will block low, you may have just gotten yourself a combo.
Mixuping includes B+K B K/2K, a perfect mid/low mixup that will crumple either way. 66KAK is also good at this, but you can duck under the A, and thus it becomes less effective. Crouch Dash itself is a mixup, because you have either a hit comfirmable low string, a fast releasing mid attack throw (that leads into K or 2K for a mid/low mixup) or a high launcher. If you don't know how to wave dash, you keep doing 236.
Well, starting an offense can happen in a few ways. The most common should be punishment with EWGF if you can do that, or maybe a nice AAB into a wall. 66B+G also sets up for an EWGF and puts you at an optimal position to start mixuping. Additionally, 88/22 KK and 88/22 BB are great step punishers, which can lead into FLY K or any number of EWGF, 3AB BE, and 8B+K combos respectively.