using the USB programmer is really easy to program ESP8266.
to connect the sensor all you need is to plug the sensor into the I2C adapter. i prefer to use these adapters because they make so easy to connect hardware, without these plug and play adapter there is a lot of risk of making wrong connection. A bad wiring can kill your wifi as well as your sensor.

to show the sensor o/p on a webpage i wrote a very basic script which will read the sensor data and will display in a browser.

I dont have much exp with html. so i just wrote a simple example app that how you can display your sensor data from ESP8266 to a webpage.

this code will read the temp & humidity using the sensor HIH6130 and will display the data on a local webpage.

reading sensor data is really easy. please check this code for reading temp and humidity.

i displayed the sensor data on arduino serial monitor as well as on a local web page.

as you can see they are showing the same output.