Dextrose -- I think that's a fancy name for sugar. I think it's hard to avoid in processed meats like bacon. A little bit (like for me, 2 g a day) probably won't hurt.

Natural sugars in things like salad -- do you mean naturally occurring sugars in something like Romaine lettuce? If it is a low glycemic index veggie, I wouldn't worry about it. Atkins has a list of veggies -- check his book or his web site if you're unsure about a particular veggie.