Compared to the rest of the Seattle Metropolitan Area market, the Tukwila region has less expensive rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 23 listings have come on the market, which means spaces most likley are going fast. You'll want to be prepared to tour spaces as quick as possible. About 4% of the listings in the Tukwila are subleases, so you will probably have to consider a longer term lease. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,460 sqft. Most properties in this region are around 2 floors. Most buildings in this area were built in 1979 and are Class A.