You can ask the restaurant to prepare your food so that it's spicy or mild. There are chicken dishes, beef dishes, and many, many vegetable offerings like gomen, which is a spinach dish. And don't get me started on the lentils!
If you're interested in trying out a delicious Ethiopian restaurant in the City, there are several places you can go. My favorite thus far is Dukem Restaurant on U Street. We had to wait for a table, but it was worth the wait! The waitresses wear what I'm assuming is supposed to resemble traditional dress and are very friendly. Excellent restaurant guide ratings line the walls and I understand it's always crowded - so I'm not the only person to agree it's delicious. If you've not tried this cuisine before, break out of your shell! Try it!