Peel and dice the cucumbers and onion, and add to a salad bowl. Dice the tomatoes, and add. Peel and dice the avacados. Juice the limes over the vegetables, add all the seasonings, and mash together coarsely. Add your lettuce, cilantro and seeds, and toss.
I didn't use jalapeno, but this or any other pepper to taste would have worked fine. You could also use nuts instead of sunflower seeds, add cheese, add beans, or whatever other salad enhancements you enjoy.