How can I make my black beans less dry? The dish is simple. I usually just boil beans, add sautéed onions and garlic, season with cumin, then eat with steamed rice. I love the flavor as it is.

I have a problem with the texture. If I leave the water in the beans, the dish becomes, well, watery (I don't want soup). If I drain the water, I'm left with a rather dry rice and bean dish.

Rather than draining the water, I'd like to add something that would change its texture.

I've tried thickening the dish with flour and cornstarch, but I end up with a pastey texture. I'd like a more syrupy/creamy texture (think baked beans from a can).

Suggestions?
What I would suggest is rather than adding a syrup, to take some of your cooked beans, cook them a bit more, then liquify them in a blender. This should give you a thick sauce that tastes like the beans, therefore compliments them perfectly. You can then thicken them very slightly if the consistency is still too runny, be sparing with the flour though. 

In fact, you could probably make something satisfactory by simply using less thickener. If you have a pasty, sticky sauce it's a classic symptom of too much thickener. Try making a roux with some butter and flour, cook it awhile for a dark roux which gives deeper color and more flavor. You can then add the roux in small amounts to your cooking liquid until you get the right consistency. 

If you are pressed for time and have some available a couple big spoons of refried beans may just do the trick too.