Colleges in Canada

You should be able to. You can write to the college to confirm your eligibility as only the admission officers can tell you the best options for you.

The process depends on whether, you are applying to undergraduate course or postgraduate. So, please mention the level of your desired course.

Hi Gagan,
After completing the Diploma, you have the option to complete Bachelor of dental sciences at UBC and a Bachelor of health sciences from TRU. To start looking for jobs, you must acquire a license first, to be eligible for registration and licensure with the College of Dental Hygienists of British Columbia.
Graduates must pass the national dental hygiene certification examination. It is better, if you obtain a Bachelor's degree for better job prospects and later think of a PG level qualification. Please note that programs intake is under review. So, contact the college directly before applying.

There is no average salary figures anyone can provide you. The reason being that the kind of job you will get after finishing the course will depend on how good or bad you are at your course.
You can check the college's website here to get more information.
http://www.sfu.ca/career/WCID/faculty-of-applied-sciences/comp-sci.html

There are many community colleges which offer this course so you may go through the following link and decide.
http://www.schoolsincanada.com/42726/Algonquin-College

You should have a good academic background. You need to have at least 1year of work experience. Also, score good marks in IELTS.

Shri Mata Vaishno Devi College is the best as it takes admission on basis of JOSAA. It is a government institute.
All the best.