I think that cooking couscous in a flavored liquid is the best place to start for yummy couscous; I usually microwave 1 cup of couscous with 3/4 cup chicken stock, 1/4 cup water, and the juice of 1/2 a lemon - three minutes is all it should take, and then fluff with a fork. At that point you don't really need to add anything else for flavor and this makes a great side dish for chicken meals..
Otherwise, I think the ingredients for a couscous salad are the same as a pasta or rice salad - throw in whatever you like and dress it with good olive oil and vinegar. Roasted vegetables and pine nuts; greek salad (cukes, red onion, black olives and feta cheese); tuna, corn, and tomatoes; chunked chicken, walnuts, arugula/rocket, and chopped apples, etc.
IMHO it's not a good candidate for freezing, since it's just tiny pasta and might turn to mush when defrosted. You can microwave a fresh batch in the same amount of time it would take to defrost anyway.