Lectins can be reduced (but not eliminated) in grains by sprouting and boiling. Baking, however, doesn't significantly reduce the amount of lectins or gluten in wheat products.
Lectins can be reduced in beans by extended soaking, fermenting, or prolonged boiling (raw and/or sprouted kidney beans are actually poisonous because of their high lectin content). Fermented soybean products, such as tempeh, are lower in lectins than other soy products.
Fortunately, there is an exception to every rule: white rice. The lectins and storage proteins in white rice have a lower potential for harm. The carbohydrates in rice are broken down completely and typically don't contribute to bacterial overgrowth in the gut.
As always, it's best to consult a doctor or dietitian before starting any restrictive diet. While there are little clinical trials to say whether lectins are "good" or "bad," if you find yourself sensitive to lectin-containing foods, experimenting with a lectin-free diet may be beneficial. You know your body best—so feel free to eat or avoid what feels right for you, whether it's lectins or not.