Meanwhile, drain clams, reserving 3/4 cup of the liquid. Heat oil in a large skillet over medium-high heat. Add garlic and crushed red pepper and cook, stirring, for 30 seconds. Add the reserved clam liquid, lemon juice and salt; bring to a simmer and cook until slightly reduced, 2 to 3 minutes. Add tomato and the clams; bring to a simmer and cook for 1 minute more. Remove from heat.