It's great to see guys taking an interest in nutrition! The good news is that you don't have to worry about water retention, you just have to not eat things that're bad for you.
Desire for bad foods is fueled by our bodies and what we instinctively know about the nutrients things contain. You're drawn to bad foods because they have a lot of simple sugars, fat calories, and other things that make the lazy systems of our bodies think they're getting a really good deal. At the same time, healthy snacks can be a turn off either because the nutrients in them are difficult to assimilate (like raw vegetables), or because they're loaded with nutrients that we don't actually need.
The trick, then, is to find a healthy snack that has nutrients we do need, so that our bodies will be okay with our choices. For that you need to see a doctor, but off the top of my head let me recommend pumpkin seeds for their high magnesium content. Magnesium is a crucial component of muscle control and most people don't get nearly enough of it. They're also only 1 calorie per seed, but don't tell your body that.
The recommendations for nuts and trail mix are, unfortunately, questionable ones. Nuts contain a ton of fat calories, and although they're mostly good fats, you can only take so much solace in that. Trail mix is especially bad; the point of trail mix is to give hikers a substantial energy boost without a lot of food. If you snack on trail mix, you may as well snack on those whole meal tablets of the future, because you're getting condensed calories, proteins, and fats, and probably putting them away like they were much lighter foods. You don't want to snack on that unless your metabolism is working overdrive. If you're dieting, I assume it's not.
Personally, I like to eat a lot of fruit. Your body will like the simple sugars, and you're getting them from a healthy and relatively low-calorie source. Plus I just feel happier when I'm getting enough fruit. I have an apple, orange, banana, and a cup of pineapple and some berries almost every day. I don't understand people who don't like fruit, and I would say if it's not very appetizing to you, perhaps you haven't found the fruit or brand that's perfect for you. Try something a little different.
Popcorn is surprisingly low-calorie as long as you make it yourself and don't put butter on. Oil popped popcorn is decently healthy, but air popped popcorn is excellent because it cuts out the calories of the oil. You can get an air popper for about $25. Some salt is not going to kill you, especially if you're coming off of sodas.
For dipping things, try out some mustards. Mustard is nearly a zero calorie food, just watch out that you don't get a blend that includes mayo, because that's just as unhealthy as mayo. There are some really good mustards out there- I like the spicy kinds.
Keep in mind that your body takes upwards of half an hour to tell you when you've had enough of something. Your eating technique can be as important as what you eat. Try to draw out your snacking, or at least do it with something insubstantial like popcorn. If you can hold an accurate count of the calories you're consuming, it will help you much more than gauging by your hunger.
I hope that helps.
