The question is why you're avoiding them/giving them up. If it's because of medicines, then eliminating citrus will probably do it (grapefruit especially).. Kiwi and watermelon are acidic, but they aren't what's going to cause bad reactions to medications. Grapefruit is the prime culprit, and lemons and limes could be an issue. A little won't kill you, but they'd have to be highly diluted (i.e. a slice of unsqueezed lemon in water soaking for 5-10 minutes will be fine.)
If it's for dental health, a straw and cup of swishing water will do you a world better than giving up fruit entirely. Blend it, drink it through a straw, and swish your mouth with water after you stop drinking and when you're done with every meal.
If it's because of food intolerance, then honestly acidic fruit might not be the only thing you're intolerant to.. There are step-down diets that have you eating the most agreeable, plain food.. and each week you introduce something new into it, and see how your body reacts to it. It's the most logical, methodical way to figure out what you're intolerant to.. but it also is a long process, and requires a lot of effort and time to put into.
I'd do two things in this case:
I'd work backwards--and just cut out citrus, and see how it goes, then if you're still having x reactions, try cutting out something else like milk and see if it changes. If the issues stop, see if citrus coming back will cause it to happen again.
I'd eliminate and be mindful of bad food combinations.
http://www.mindbodygreen.com/0-3615/10-Common-Food-Combinations-That-Wreak-Havoc-on-Your-Health.html This guide is particularly hippy, but it's easy to read.. there are smaller increments one can work with.