Heat a large skillet or wok over high. Add oil and curry paste and cook, stirring, until fragrant, about 1 minute. Add chicken and cook until starting to brown, about 1 minute. Add snow peas and pineapple and cook until snow peas are bright green and tender and chicken is cooked through, about 3 minutes. Stir in basil and fish sauce and season with salt. Serve with rice.