I'm giving pickling cucumbers another shot this year. Last season I only got two jars worth from my six cucumber vines lmao. I lost them pretty early in the season because of a wind storm.
This time I'm starting them nice and early (probably too early, we'll see) in the hopes of getting a longer season out of them.
Starting from seeds is a good idea, you'll have a plant that is better adapted to the local climate that way. That said, spring onion is a great first plant to grow, and you can just use cuttings from the ones you buy from your local grocery store (I would suggest you plant them after they have roots and few inches of leaves though). Once they have grown enough they'll flower and produce about 100 - 200 seeds.