I agree that it's best not to use the student's native language. Having said that, I find it difficult to teach beginning students on the internet (voce and video chat) without using their native language to some degree. This is because it's so much more difficult for the student to perceive subtle audio and visual clues without being face to face. I"m sure there must be a technique that can overcome this difficulty.

Using ICT (Information and Computer Technology) in an ESL classroom is a very useful tool. There are many interesting websites that provide lessons, fun activities to learn, flash cards, audio and video lessons, etc... They are enjoyable and they stimulate pupils' imaginations, enhance their creativity and make the life of the teacher easier...

Your native language can be used only as a last resort when all the methods and attempts to explain something fail. I know, for example, that ESL students find it difficult sometimes to understand some abstract nouns such as 'depression' or 'happiness'. That's why the teacher resorts to his native language so that his students can understand the meaning of these words. However, the teacher should not resort to his native language every time his students fail to understand something. There are many effective ways that can help the teacher not only to teach English as a second language but also motivate the students and encourage them to learn. Using visuals aids (pictures, flash cards) in an ESL classroom is an effective way that can motivate the students to learn and help them understand the language. Using music in class is another motivating and useful method. Nonverbal cues such as body movements, gestures and facial expressions is another effective way.

As an English teacher I find that a mixture of both methods works best for ESL students.