Heat 2-inches vegetable, canola or corn oil in a deep skillet or pan on the stove over medium heat. You want to make sure to use an oil with a high smoking point - olive oil will not work for frying tortillas. You'll know the oil is ready when it begins to appear glossy or shimmery. You can also test it by sprinkling a few drops of water into the oil - if it sizzles, it's ready. If you're using a thermometer (aff), you want to oil between 350 and 375 degrees F.

Gently and carefully slide the tortillas into the hot oil. Do not crowd them in the pan - the tortillas should not be touching. It's usually easier to fry one tortilla at a time, depending on the size of your skillet. 

Flip the tortilla once, and fry for a few minutes total. The tortilla will start to turn a golden color; just be sure to remove it from the pan before it starts to really brown. The amount of time will really depend on the temperature of the oil but they will continue to crisp up as they cool.

Place the fried tortillas on a paper towel lined surface to drain and immediately sprinkle with a little bit kosher salt for flavor. 

Top each tostada with refried beans, lettuce, cheese and chicken. Serve immediately.

Set up a garnishing station with things like avocado, sour cream, tomatoes, olives or cilantro so that each person can customize their own chicken tostada.