To answer the yoghurt dressing question - I tend to mix greek yoghurt, a bit of olive oil, some lemon juice as a really basic one. I add honey and/or mustard, herbs, garlic etc as needed.
I like the butter bean idea. I think I'd do it with burrata instead of ricotta though.
We had a lovely, but basic salad last night of mixed leaves (includign some rocket), sliced red pepper, toasted pine nuts and avocadoJust olive oil and balsamic on top. Really good as a side to the jacket potatoes we were eating.
I sometimes do a sort of Asian style salad at lunch. I buy gyoza that you just have to fry/heat up. Then I use rice noodles, julienned carrots, peppers and cucumber topped with whatever fresh herbs I have lying around - usually mint and basil, but parsley and coriander would work well. Then I make a dressing which is roughly 2 parts soy, 1 part honey and a little bit of sesame oil.
I also like a fairly basic caprese - avocado, mozzarella and tomato. Topped with fresh basil, some olive oil and a drizzle of balsamic then salt and pepper.