Kali and eskrima are known as weapon based systems, but they do have empty hand techniques, many of which are derived from the use of weapons. There are pros and cons to this. No weapon is the same as an empty hand, and the use of weapons tends to focus thought and action to those weapons. That focus can be good, and it is often very important. Against a knife attack for example, it makes sense to concentrate almost entirely on avoiding or gaining control of the attacker's weapon bearing limb (see this page for examples). But alternatively, if you tried to get control of an unarmed attacker's right arm, he'll very likely strike you with his left. This poses problems for many commonly taught empty hand applications.
Some techniques that make a great deal of sense in weapon vs. weapon combat make very little sense in unarmed fighting. Similarly, some techniques that work well in fighting with long sharp weapons don't work well with short blunt or sharp objects, and techniques that work in stick fighting may not work with swords or machetes. Therefore, all of the concepts and techniques used in weapon training should not be transferred directly to empty hand fighting.
A great example of ineffective empty hand applications can be seen in commonly taught limb destructions or guntings. Many systems and schools teach these techniques with both palm sticks and empty hands. On my palm stick page, you'll find examples in both video and pictures of limb destructions done with a palm stick, and why they don't work well. In the video at the top of this page, you'll see empty hand/unarmed examples.
With a sword or machete, it makes a great deal of sense to evade an attack and cut an attacker's arm (limb destruction), sometimes cutting his arm clear off his body. The range is great, and you can do so without getting cut. With a knife, it makes much less sense. Because knife range is so much closer, and the knife is less likely to instantly stop an attack, attempting to cut rather than control an incoming knife attack, even if it succeeds, may still result in you getting stabbed or slashed. In unarmed fighting, the situation is even worse. With multiple, unknown strikes coming in, all at close range, it will be nearly impossible to target specific places on an attacker's incoming arm. And even if you were to succeed and nail an opponent hard in the biceps, it's unlikely to make a difference. With adrenaline flowing, your opponent probably won't notice the strike, and the other hand will be hitting you as you strike his arm.
Guntings or limb destructions are a great example of weapon applications that really don't make sense in unarmed fighting, despite the fact that countless variations of them are taught in Filipino martial art schools around the world. With that said, there are times where attacking limbs makes sense! But it's best to do so when you've already got substantial control over your opponent.
The best empty hand applications of kali weapon techniques come from a combination of unique angular footwork, cover, and unique angles of attack. Footwork is extremely important when you're dealing with weapons, when one hit can literally kill you, and most kali systems include very effective triangular footwork that can be used in empty hand fighting. This footwork involves cutting and taking off at sharp angles, moving to the outside of your opponent's range. When angular footwork is combined with cover (that mirrors the same cover provided by sticks or swords), it temporarily puts you in a very safe place from which to launch an attack. On this page you can see examples of triangular footwork with 4 angles of attack and defense/cover. And here are examples of 6 angles of attack. Combining superior position and cover with unexpected angles of attack is a fantastic combination.
In addition to the video above, here are a few examples of empty hand techniques derived from kali:
If you'd like to learn more about kali, including training with weapons, see my kali section.