Hi,
I really just started to experiment last year. Like you i had a glut of rocket and salad leaves, especially lambs lettuce.
You can do a really simple pesto recipe, I use a tiny food processor and put in 2 (large) or 3 (small/medium) garlic cloves, 2-4 table spoons of green stuff (rocket/salad/basil/coriander, etc), or as much green stuff as my food processor will take, give it a wizz, push the stuff down, giv it a wizz, and then start to add oil - I use extra virgin olive oil - about 2-3 table spoons, all the while wizzing the food processor while adding the oil - you will know the pesto is right when it goes round smothly. There are two other common ingredients - pine nuts (1 teaspoon) and Parmesan cheese (about 1 table spoon). The adding of the pine nuts and cheese makes the flavour milder and smother, without it these the flavour is quite intense, and I like it.
I have kept in the fridge for about a week to 2 weeks, and I think you can freeze it.
If you have alot, you can experiment and find a balance you will like. The tiny food processor I have I found to be brilliant for this kind of thing, as you can only put so much in it!
Regards
Dawn