Hi Dannie, welcome to garden.org.
Yes, some citrus are very thorny. If you have the patience you can clip off the thorns that are in your way.
Most citrus are grafted onto a sour orange root stock. I'm not sure you'll get a Satsuma from the seeds of a Satsuma orange, necessarily. But in any case it does usually take between 4 and 6 years for a tiny plant to grow to fruiting size. Hate to say it but to be sure of getting the oranges you want, within your lifetime you really should probably go to a nursery and buy a small grafted tree.
Here in Florida we're advising people against planting any citrus trees of any kind until the Citrus Greening disease epidemic is under control. The UF boffins have hopefully found a silver bullet for it, but it's not for sure yet. You should find out from your County Extension service if there is Citrus Greening disease in your county.
