Yes, Rays love earthworms and nightcrawlers as part of their diet. They may not love them as much as blackworms, but they are an excellent source of nutrition. Smaller rays will have a hard time eating whole earthworms, but chopping them up in smaller peices might be necessary until they can stomach a whole one.
I use 'cricket forceps' that you can buy at PetCo for 2.99. I use them to pluck out nightcrawlers, which I will rinse and then dangle above the tank, and chop into 1/4's with scissors. I don't get my hands dirty in the process, and all I have to do is clean the utensils when I'm done.