Gravlax aka gravadlax is extremely easy to make. After it's made, it can be frozen and will keep very well for a very long time.
I just cured what started as a beautiful 14#, before trimming, Scottish salmon (more than 10% fat!) a couple of weeks ago. I started by trimming the salmon well (your fishmonger will probably do that for you), including cutting about four or five inches of the tail to freeze and hold as uncured fillets.
When you make your gravlax, you can cure it as quickly as overnight, or for as long as three or four days (although that will involve refreshing the "cure"). I prefer a longer cure, myself.
Cures are almost always very simple, to the point where someone who knows her way around the kitchen as well as you do doesn't really need much of a recipe. For instance, my last one was 3 parts kosher salt, 2 parts sugar a little white pepper, copious amounts of dill, and a splash of vodka -- aquavit is a nice substitute for the vodka, and so are gin and tequila.
For my large salmon, I made roughly 1-1/2 cups of cure, then refreshed the cure and dill two days later with about half the original amount.
I put the salmon in a pan flesh side out, splashed it with vodka (Hendrick's Gin would be a great choice); put some dill sprigs on the fish, covered it generously with cure, laid some more dill sprigs on one side; then laid one side on another -- flesh to flesh and skin out, and tightly covered the curing pan with cling wrap.
Some people like to wrap the salmon itself in cling wrap -- it's a neater package, but the excess moisture won't press out as well.
During the curing period -- three days in this case -- the salmon was pressed under a weighted pan in the fridge; and turned and drained once a day. Over the three days, the salmon lost at least two cups of liquid -- maybe more.
When the salmon was finally cured, I sliced one whole side very thin -- about 1/4 for my refrigerator (still have a little), and the rest wento into the freezer as a gift for my father who will receive it tomorrow. The other side, I cut into thirds, wrapped each separately and froze. I'll, be defrosting and slicing one on Monday.
I imagine you're thinking of portioning your salmon, and reserving a part of it in much the same way. Be of good cheer. You're fine.
If you want more detail -- as in an actual, written out recipe -- just let me know, and as always I'll be glad to oblige. That said, almost any uncomplicated recipe will work well. Mine is nothing special.