As with pastic models, a wash in hot soapy water before you start is a good idea, as they often have a quite oily residue on them that will interfere with glue or paint.
Glue will depend somewhat on the specific plastic used, and the surface texture... some of these tubs are smooth, some have a bit of a rough finish which will cause superglue to not work as well. A quick-setting Epoxy glue would probably work, although I've been using one like this:
http://www.loctiteproducts.com/p/sg_plstc/overview/Loctite-Plastics-Bonding-System.htm
It's essentially a strong superglue formula with an activator... You 'paint' the pieces to be glued with the activator, add a drop of glue and press them together. Bonds almost instantly on just about any type of plastic.
I've had no problems with spraypaint sticking to the tubs I've been using, but success there may vary depending on the specific plastic used. I've undercoated with both regular spray paint and a 'undercoat' spray, and both worked fine. Otherwise, a coat of matte sealer first might help.