Light salt on the melon works well to bring out the taste. If you don't think salt does this, make some oatmeal without it (or if you don't put salt in your long boil oatmeal, try it by the package directions.)
My Grandma always put a little black pepper on her cantaloupe slices.
Salted watermelon does not taste salty. I'm not much on salting things, but you could salt one single bite to test. You might be surprised. It doesn't take away the sweetness. You'd have to drag it in margarita salt to do that.
Had some this weekend. I use salt AND lime. I salt and lime apples and cucumbers too. There isn't much I don't put lime on. Now that I'm pregnant I've been drinking a lot of mineral water with lime and salt. I always thought it was a mexican thing.
I don't cook with salt, don't have a salt shaker in the house, don't put salt on anything I eat, except one thing-watermelon.
A good thin skinned Mexican lime is really good on there, too.