I noticed tonight that there was a puddle of coolant under my FC. It appears to be coming from somewhere near the engine. I checked many of the hoses I could see, but none of them showed evidence of leaking coolant.
I looked under the car, and there was green stuff dripping from the pan (radiator pan? I don't exactly remember what it's called. )... The overflow bottle was completely empty.

How should I go about finding the leak and fixing it? I'm still pretty new to the world of rotaries.
My car is an 88 TII.

Here's a lovely picture of the green stuff dripping:

 

I would start by putting the car on stands and taking that pan off and looking for the leak.

 

Pull the bellypan...right now it's just hiding the water trail.

Fill the car with coolant and start the engine, let it idle till the gauge reads normal.

It should be pretty obvious now which part of the engine has the leak.

 

looks similar to mine right after i put the engine back into the car and filled up the engine and radiator with coolant.

check the hose that runs from the drive side of the engine to the heater on the firewall. having a hard time finding it? look beneath the oil filter pedestal and you'll see a hose, follow that hose. you can also easily check if you get under the car and look straight up at it. if you see coolant dripping down the sides of the tranny tunnel, then congratulations; you found your leak.

a harder-to-get-to leak that it could be is the coolant hose that runs from the backside of the UIM to the firewall. this one isn't too difficult to fix. the one you better hope it's not...is the hose that runs from the rear iron(side housing?) to the bottom of the upper intake manifold. saying it's a pain to get removed/replaced is an understatement.

all in all though, if the pool seems to be forming on the driver side of the engine, it's probably the first hose i mentioned. if the leak seems to pool on the passenger side of the engine, it's likely one of the other hoses i mentioned, or could be one of the ones on the BAC valve(given if you still have it)

 

^^ I think it's that one.

So what's the best way to fix this? I've tried tightening where the hose connects to the engine, but to no avail. I figure the hose has a hole in it somewhere. How do I replace it?

 

Well I fixed it. I ended up taking the end of the hose connected to the engine (and coolant started pouring out everywhere--as it should, I s'pose), and cutting off the end (It wasn't in very good condition. Looked like it had rust-colored sand in it, and was way too soft.), and reattaching the hose where I took it off. Added some new coolant and drove around the block a couple times till it warmed up. No more leak.